Doing my head in - High nitrates

[larrymull]

Hi Guys,

My nitrates continue to read above 20, sometimes 40 and I have no idea how to keep them down. All other parameters are fine ph 6.2, 0 ammonia, 0 nitrites, 2kh, 4gh, 195 TDS (it has crept up a bit too much for my liking).

Anyway some simple things for you to know is that my tank has a layer of frogbit, I do not overfeed (feed every 2nd or 3rd day), weekly 10% water changes using RO water, I also have boss mineral balls, IAL leaf, Benibachi zero, golden vine with xmas moss, 1 aqua clear hob filter and a biospon 56l dual sponge. 

I do not want to go down the path of using peat moss, I just want to be able to control the nitrates naturally. 

I would appreciate any thoughts - my plan of attack this weekend is to do at least a 25% water change (this takes forever to do when you are dripping the RO water back in to the tank) and was going to clean the sponge in the HOB filter.

[Ronskitz]

Id start with the filter as it may have restricted flow and not able to keep up with clearing the nitrates but still doing the nasty ammonia and nitrite. Then just perform a 10% wc every 2-3 days and see if that helps. There are others on here with much more experience than me so they may chime in soon. Any nitrates that are in the water body itself should be consumed pretty quickly by the frogbit

[kizshrimp]

Lucky you're not planning to use peat moss, because it will do nothing to reduce your nitrate levels! In fact it may contribute to them slightly. 

The N levels you're measuring probably have little to do with your feeding rates - active substrates seem to keep leaching nutrients indefinitely. It's all being cycled efficiently so you don't see an ammonia or nitrite reading but you do end up with high nitrate as the end product. There's 2 sides to every coin and this is the dark side of our popular active substrates. This is why SOP with fish has always been to use inert substrates and control the parameters with decent husbandry practice. 

Frogbit is a decent nitrate sink - most floating plants are - but I don't think it will get you there alone. Ceratopteris (eg "Water Sprite") is bigger, more vigorous and will therefore pull the nitrate out faster. Duckweed is excellent but messy. My sumps are literally full of these 3 plants and that's pretty much the volume it takes to control nitrate. Most shrimpers seem to like neater looking tanks so this approach is unsuitable. You could improve the plant growth and therefore nutrient uptake with fertilisation. It's likely that iron and potassium are low. Better light helps big time, obviously. BTW the plant growth approach (nutrient export) requires regular removal of plant mass from the system - that's how you're removing the nitrogen. Leaving it all in there won't help. 

You could use something like purigen or macropore to pull out the organics before they contribute to the N levels. Or carbon to pull out everything. Some people use anaerobic and/or chemical denitrators but these can be complicated, sometimes unreliable and not cheap. 

Big water changes work too but are not so compatible with shrimp keeping. That's why after cycling an active sub tank you do a massive water change before adding livestock - to drop the accumulated nitrate right down. I'd suggest that combination of these approaches is what most people are doing. 

Once you've got the new water dripping into the tank, go do something else for a couple of hours... the time passes way faster. 

[Callan]

What are your stock levels in the tank. It seems very strange that you are getting such high nitrate readings considering the amount that shrimp add to the bio-system would be very small.

Kiz has given you some really good advice in what he has written and I would be definately be taking it on board. From what you have written it is not that you are feeding too regularly but I wonder about the amount of food you are feeding. They should only be feed enough food that can be consumed fairly quickly. The same with fish.

I would definitely be adding more plants to help absorb the nitrates and would do the water changes that have been recommended above as well as cleaning the filters at the same time using the tank water.

The other thing and I may have missed it is to add air to the tank. The bubbles help to push the nitrates which convert to nitrogen gases out of the tank and therefore reduces the nitrate levels. I have explained this in very simple terms and I would be getting this happening lower in the tank as it will work more efficiently.

This principle called sub air aeration is used in larger ponds for this exact reason and I specifically have used it in the koi ponds I have built. It helps to improve the filtration by reducing the nitrates and therefore also keeps the water cleaner and clearer.

The other thing you could try and is 100% safe is Aquatek pond clarifier. It takes about 8-10 weeks to start working effectively and is added in powder form to the tank every two weeks. The only thing is you must add it every two weeks or it wont work and continue to add it on an ongoing basis. A 15ml scoop treats 2000lts so initially it about the $22-24 mark for I think 248gms but considering how small of an amount you would use it will last you ages and therefore would be very cost effective.  I have seen the results of this first hand and would have no issues recommending it.

It is as I said 100% safe, you physically cant over dose with it and the shrimp could eat it and it would do nothing to them.  If this interests you let me know and I will put you onto the nearest stockist for you.

 

These are the only other things I can think of to help you other than what has already been mentioned above. 

Edited September 4, 2015 by Callan

[salvanost]

use salvania natans

use lot of them, make sure to cover at minimum 75% of tank surface, it's a minimum to stop the nitrate going higher than 20

 

make some tools to make hole at water surface to make sure inside tank got sufficient light

 

 

[larrymull]

Thanks @kizshrimp @Callan and everyone else. I will try some of your suggestions, please note there is only about 20 shrimp at the moment living in a 60l tank. I do aerate the tank through the sponge filter.

[Callan]

The sponge filter would be emitting the oxygen out towards the top of the tank and therefore there would be approximately 70 -80% of the tank not being aerated. Try even pitiing an air stone down lower and see if it helps. You can split line going to sponge filter. Nothing to loose.

If you decide too I would take a reading at setup, then take a reading 24 hours later, then 72 hours and see if the nitrate levels are dropping. Also try to get the airstone as close as possible to the centre of the tank. It may look ugly but see if it helps and if so you could always disguise it a bit.

[kizshrimp]

Aussie keepers please remember that Salvinias are listed as noxious weeds where they occur here. If you do use it don't dispose of it irresponsibly. The compost heap is best. The advice from salvanost to cover at least 75% of the surface is consistent with my experience with other floating plants anyway. 

I have never heard of aeration dispelling nitrate to the atmosphere as N2; my understanding is that anaerobic conditions are required for that phase of the cycle. I would love to hear of the mechanism by which this suggested approach works. 

[inverted]

Not sure how you filter is set up ..... Clean sponges or wool. If you have bio media in there as well you could replace your sponges/wool.

Give your gravel a good vacuum! Sometimes this is the source of creeping nitrate if you have everything else balanced!

Edited September 4, 2015 by inverted

[Callan]

Nice thinking inverted about the substrate. Didnt even cross my mind.

[Callan]

Aussie keepers please remember that Salvinias are listed as noxious weeds where they occur here. If you do use it don't dispose of it irresponsibly. The compost heap is best. The advice from salvanost to cover at least 75% of the surface is consistent with my experience with other floating plants anyway. 

I have never heard of aeration dispelling nitrate to the atmosphere as N2; my understanding is that anaerobic conditions are required for that phase of the cycle. I would love to hear of the mechanism by which this suggested approach works. 

Kiz, either I have written it badly or you have misread what I wrote. Sub air aeration is very widely used throughout the world and in fact the most popular form and in most circumstances the only form of filtration used throughout America. Especially on large ponds, dams, lakes etc. 

There are also systems that are operated via windmill but these are slightly restricted due to the windmill only being able to run one aerator.

The research shows that the nitrates within the water body convert to nitrogen gases and whilst the plants absorb the nitrates they can only absorb so much as you would be aware. The remainder of gases stay within the water body. This is even worse in deeper depth of water. 

I should also add that the research shows that oxygen depletion occurs in deeper water and that even surface type aeration is only effective even if being dropped into the water ie. say a waterfall in the best outcome to 1/3 of the water depth.

So sub air aeration releases air via either a larger verion/s of air stones or through a manifold system. These come in singles, doubles and quads. The other advantage is that it is very effective in odd shaped ponds etc or where there may be dead spots as far as flow or water movement goes.

So in its basic form the aerator sits on the bottom of the water up to a depth of 2-3 metres (the deeper the bigger the compressor must be) or they can even be fitted to floats in some circumstances.The air bubbles then create water movement and it pushes these trapped gases up to the water surface and is expelled into the air.

In relation to your comment about anaerobic bacteria requires water movement and oxygenation to successfully grow and multiply quick enough. No water movement no aerobic bacteria. Anaerobic bacteria will multiply kill off the aerobic bacteria and also at the bottom of the water will create a film that will completely starve the substrate of oxygen, killing everything eventually from plants to livestock.  

This results in reducing the bio load both in the water volume itself and if being used in conjunction with a pump and filtration system also reduces the load on the filter.

I have not only installed numerous systems but have also tested it on my own pond using air stones and an air pump. The end result was that the water was and stayed much clearer and the other reason that I tested it was that I was also having issues with string algae. I found that it produced results of up nearly 100% of the string algae not regrowing in my ponds. This was simply due to the fact that because the nutrients that it was feeding on being greatly reduced and the plants absorbing the remainder it had nothing to feed on.

 

 

Edited September 5, 2015 by Callan
Added more info

[kizshrimp]

I don't really like having to make these corrections here - it feels confrontational, not what I want at all - but they need to be made. Misinformation is such a problem in this industry and/or hobby. 

"The research shows" that anaerobic bacteria convert NO2 to N2. They use the oxygen to drive their metabolism because it's not freely available in the anoxic conditions they require. The required conditions are quite specific and not always easily achieved. Normally a dedicated anaerobic module is incorporated into the filtration pathway, with the first stage of aerobic nitrifiers depleting the oxygen level sufficiently for the anaerobic denitrifiers to function as desired. 

The aeration systems you describe are widely used in sewage treatment, aquaculture and elsewhere to provide a suitable environment (oxygen-rich) for AEROBIC nitrification. This process is familiar to anyone who manages an aquatic environment. Consequently, with ample oxygen available in the water, plant roots are able to efficiently uptake the nitrate produced (and other nutrients, like phosphate); the net result is a reduction of free nitrate and other accumulated nutrients but the mechanism is completely different. And the nutrients aren't gone, they're locked up in plant biomass until it's removed. NH3 can be gassed off with violent aeration but the process isn't efficient until about pH 10, simply because too much ammonia occurs as NH4 below there. 

There is no argument that deep water aeration is a great thing. I'm sure you remember the Botulism crisis at Ringwood Lake a few years ago. There is no argument that stratified layers in the water column are normally undesirable.  But does aeration promote anaerobic denitrification? No. Does it convert nitrate to N2 by some other mechanism and then expel it from the water? No.  

 

[Callan]

Hi Larry,

The seems to be a difference of opinion into the usefulness of these systems and the results of what they do or don't do.At the end of the day it isn',t a weeing competition  It up to you wether you try it or don't try it. Don't get caught up in trying to get your head around the sciences of it all. It will just confuse you more. I would just use the KISS principle. 

All I can say is I have installed numerous systems and seen the results both professionally,personally as well as numerous positive feedback from customers. If you would like more info about this subject for your own knowledge, PM and I will put you onto the importer, who I know personally. He is in a handful of people within Australia with the expertise in not only this subject but all aspects to do with water quality. He is also the only person in Australia who has successfully built natural swim ponds. Another interesting project and topic. These are more popular in European countries there has only been two built to this stage here.

Inverted's idea in relation to the substrate is a good one and that alone may make a huge difference.

Edited September 6, 2015 by Callan

[larrymull]

Thanks @callan and everyone else. Well on the weekend I did a 20% water change, cleaned the foam filter and did not do any feeding. The substrate is quite new approximately 3-4 months old and there is hardly any wasted food I can see between cracks. I also checked my API nitrate expiry dates and found that these expire in 2019. I shook the bottles and banged the bottles for what seemed like 5 minutes and then tested the water (i had waited for 24 hours). The results were exactly the same as before if not slightly a little better, I thought that couldn't be right and tested again, exactly the same readings. This is frustrating, the shrimp all in all look happy and I agree with the KISS philosophy. I guess the reason I am mainly trying to get the nitrates down is for the future survival of shrimplings. I have heard and read (through @shrimp daddy's blog) that high nitrates can cause lower survival rates.

 

I've invested a lot of time and to some degree money to set these guys up well and want to have a successful tank with high survival rates of shrimplings.

[salvanost]

1. u cannot reduce the nitrate with 20% water change, if u insist try to make more frequent waterchange for example from once a week to once every 5 days, i really bad with water change, too often would kill the shrimp too in my case, especially sensitive shrimp like taiwan bee

2.  before u thinking to use nitrate remover like benibachi or mosura or seachem or anything else (i'm not sure), remember there is a case where some marketed products for shrimp will make false reading to the water tester

same with other products, don't try using lot of product, i'm regret with too much product, just to realize some product would just cause new problem later...

3. i would like to say, one of KISS "S" word should mean "stable" , when my friend got more than 50ppm nitrate reading he still success breeding the prl, so i think nitrate won't be a biggest factor killing the shrimp, so just keep it simple and stable

Edited September 7, 2015 by salvanost

[larrymull]

agree with you @salvanost that i don't want to mess with the stability of the tank, that is why I am looking for a simple answer to this issue and if i don't get one and the shrimp appear ok and I have good survival rates of shrimplings, i'll be happy.

[larrymull]

Hi guys a little update on where I am at with my nitrates. Unfortunately they still remain the same and I have lost a fair few shrimp in the process. I find it extremely frustrating as I believe I am doing everything right.

I have now dropped my feeding down to once every 3 days and am still finding nitrates over 40 and shrimp deaths. When I am doing water changes I am dripping the RO with salty shrimp back in to the tank very very slowly. All parameters are good except nitrates, TDS a little high at 190. I have added more aeration and haven't seen too much difference. 

I have 3 females berried and some of the shrimplings from before have grown up well. Could we put the high nitrates down to ADA soil?

Any other thoughts would be great. I might post a video later tonight to show you my set up.

[OzShrimp]

do you vacuum your substrate? there could be waste build up underneath it. When you vaccuum it though it does stir a bit up but i always do alittle bit each water change and the amount of crap under there is amazing 

[larrymull]

@OzShrimp not really, but I only feed in one section of the tank, front right. I can see a fair bit of build up and I can vacuum next time I do a water change, but not totally convinced this is the sole problem. I am pretty sure this can cause a possible ammonia spike. 

[fishmosy]

Have you checked that your RO filter is producing water with 0 TDS? 

Also 40ppm is a relatively high amount of nitrate. Are you sure the test is OK? Have you verified this using another test kit? Expiration dates don't really mean anything. Its more important how long the test has been opened (exposed to air to which it may react).

Edited December 8, 2015 by fishmosy

[salvanost]

1. please don't vacuum ADA Amazonia soil, it's high ammonia soil

not shrimp safe if u mess with the soil

 

2. be careful with high tds, random shrimp products could lead to higher risk of failed molting

keep it at 120tds to prevent failed molting

[larrymull]

@fishmosy yes TDS 0, I might have to buy another nitrate test to confirm. However, deaths must equal something.

 

@salvanost too late already did a little vacuuming of the soil, there has been some deaths of failed moulting too.

I did a 20% water changer last night with RO water, trying to get it down the TDS.

[jayc]

Finding the cause is the ultimate goal.

But I reckon, as a temporary fix while we locate the source of the problem, you need to whip out the Macropore or Purigen. Use that ASAP to reduce your Nitrate issue.

Marcopore from TechDen is cheaper than Purigen if you don't have any and need to buy some.

 

That will buy us some time while we/you figure out the source of the problem.

[revolutionhope]

+1 macropore ftw

[larrymull]

@jayc I have put something in do reduce nitrates and as such have not had any deaths since yesterday morning. I bought also a new API nitrate kit and unfortunately I am getting the same result for nitrates which is 40.

I have another tank running RO water for CRS and RCS, and that has 5 nitrates (happy with that). Interesting that is with black earth substrate. I am now wondering if it is the ADA amazonia that has never fully leeched all the nitrates out of the substrate?

I am going to do another 25% water change tonight - I am also bringing down my TDS to 150, it is currently sitting at 180, so slowly slowly.

I was at an aquarium yesterday, not a sponsor but keep shrimp and i discussed at lengths this high nitrates that I have. They were at a loss too. They believed I would see ammonia pop up before nitrates would come through. I reiterated I had 0 ammonia and 0 nitrite.

The more and more I think of it, i am really leaning towards the ada amazonian not having full leeched all the nitrates from the substrate.

Edited December 9, 2015 by larrymull