TDS question

[Michael Petro]

I am keeping a large Cichlid tank, and a heavily planted RCS Shrimp tank , both sharing the same wet/dry filter. Basicly the planted shrimp tank is a refugium to keep the nitrates down in the cichlid tank, with shrimp added for the coolness factor. Consequently I am trying to achieve a balance of water conditions that will allow both tanks to thrive.

 

I have added an "automatic water changer" feature that is triggered by TDS. I monitor TDS and when it reaches a certain point (currently 150ppm) I do an automatic 5% water change. The result is that my TDS will rise to 150ppm and then drop 145ppm.

 

I have the ability to change as much water as I want whenever the TDS trip point is reached, and the ability to set that TDS trigger at any ppm I want.

 

My question is this, is it better to do small water changes or large ones, i.e. small TDS changes or larger ones? Water consumption being the concern, larger wtaer changes would conserve more water in the long run, but result in bigger TDS swings. Currently, it is doing a 5% water change about every 20 hours.

 

 

 

 

I let pieces of coral collect algae and mulm in the big cichlid tank and then drop them in the shrimp tank, the shrimp will totally "bleach" the coral in an hour or two. This piece was completely covered in green/brown slime an hour ago.

 

[perplex]

smaller water changes would be better, because the big ones will shock the fish and shrimp more, if you ever wants to adjust anything like ph TDS, its best to do it slowly rather than fast

 

nice looking tanks by the way.

Edited March 27, 2015 by perplex

[jayc]

It takes days for my tank to raise TDS from 145 to 150. Not 20 hours.

I believe some of your rocks or substrate is raising TDS.

If you gave the RCS their own tank, you will save on water changes. Remember I said shrimp and cichlids need vastly different water parameters?

Edited March 27, 2015 by jayc

[kizshrimp]

Michael, definitely smaller more frequent changes are better. I have to say though that 150ppm TDS is incredibly low for an African Cichlid tank, even though they're just Malawi fish. We run them at more like 300ppm GH over here with high KH too, TDS would have to be over 400ppm. Having a look again at the schematic (nice setup btw) I don't understand how your GH is 180, KH 80 and yet TDS lower than than combined total. Something is not measuring accurately. Calibrate the TDS monitor and change the water change set point higher!  

 

JayC, it's not unusual for African tanks to have alkaline buffering substrates and rock. You want to run the hardness higher than those substrates will buffer to alone and the water change regime stops levels getting out of whack. I guess in this setup the RCS have to cope with the parameters and they look fine. 

[jayc]

JayC, it's not unusual for African tanks to have alkaline buffering substrates and rock. You want to run the hardness higher than those substrates will buffer to alone and the water change regime stops levels getting out of whack. I guess in this setup the RCS have to cope with the parameters and they look fine.

yes, I know, and that's what I mean. You need to constantly change water to keep it in control. No water saving there, which seems to be Mikes concern.

[Michael Petro]

@kizshrimp - You were right, my TDS meter was off, I broke out the calibration salt and got it dead on the money, it was about 50ppm low.

Today's readings:

• Kh 6dh
• Gh 10dh
• TDS 192

To your point though, my TDS is still less than the combined kh and gh. Does it really work that way? Or is it possible that the two tests could be reading some of the same stuff. I used API titration style test kits. I am confident in the values assuming the reagents are accurate, they are less than 6 months old.

 

Also, you were spot on about the substrate, it a mixture of Rift Lake substrate and regular gravel, with large baseball size pieces of coral added in as well. My tap water is about 7.2 after 24 hours, (but 7.4 out of the tap) and my tanks buffer out around 7.4. Also spot on about the Malawis, mostly Aulonocara and other Haps, a dozen Synodontis cats, some Nerite snails, but no Mbuna, was shooting for a more peaceful tank this time. I have done a lot of Victorians in the past, I love them but they are just too aggressive for this tank.

 

Anyway, I changed my TDS meter to a setpoint of 250ppm to trigger the water changes. The rate of rise on the TDS is a lot slower now.

 

@jayc – you are certainly right. I know I am pushing the envelope here, trying to run the Africans at the lower end of their range, and the RCS and green Babaulti at the upper end of their range. I “think” I can make it work. The RCS colony is certainly thriving, lots of population growth, the babaulti isn’t yet, but then I just got them a few weeks ago. The cichlids seem plenty happy too, with frequent fry.

 

It is certainly working for my original goal, with was to reduce the nitrates in my big tank. My nitrates measured around 5 today, where they used to be around 40.

[kizshrimp]

Hi Michael, glad you found the  issue easily. I knew something was off. I am also confident your reagents are fine, in my experience the API kits don't work at all once the reagents go off. The 2 tests must be reading some of the same thing; probably KH generated largely from Ca in your system but Na or K in mine. There's others here on SKF with better chemistry knowledge than me. 

 

I think I see some Protomelas - similis or taeniolatus? An unmistakable Copadichromis borleyi juv on the left. Actually some mbuna are relatively ok but most are a problem. I too love Victorians but true they are aggressive. There's not too many here in Aus, I guess our import restrictions restrict their entry, and their lower popularity doesn't encourage the smugglers. My real soft spot is for Tanganyikans though and I feel as though I'll be setting up for some again soon. 

 

Very happy to hear your planted refugium is pulling down the nitrates effectively. Do you keep it on the same light cycle as the Cichlid display or alternating? 

[Michael Petro]

The proto is a taeniolatus (Red Empress) and is one of my faves, and yes on the C. borleyi.

 

Similar light cycle, not opposing, as some do for ph stabilization. Main reason is I want to be able to see both tanks during my normal waking hours. With the large body of water I have I dont see much ph swing and I dont inject CO2. Although I do dose a half dose of generic Glutaraldehyde (akin to Seachem Excel), and some Seachem Iron, daily. The Hornwort you see in the cichlid display is actually fresh prunings from the shrimp tank, thats how crazy the plants are growing in the refugium. Interesting that the Africans dont mess with the Hornwort, but will demolish any other plant.

[kizshrimp]

I just posted on another thread that Hornwort is the only thing we can get away with in a yabby tank. It's absolutely untouched, but he demolishes all other plants too. What is it with Ceratophyllum?

[Michael Petro]

Hehee, had to look that one up, learned something else today! Never heard of a "yabby" before, but certainly have seen them. Love the electric blue ones.

[Grubs]

What is it with Ceratophyllum?

I have Ceratophyllum in my ponds and its my plant of choice for floating in breeding tanks and there is some in my shrimp tanks too.   It does have this scary ability ni low TDS water to be shocked into losing all its needles and what a mess that makes!  This week I sold a few shrimp and to hold lots after sorting for sale I put them in coffee jars with some horwort and bubbler... in the morning I had bare stems and shrimp in amongst needles... what a mess.  Had to pick all the shrimp out one by one to bag them.  So yes.  What is it with Ceratophyllum?

 

 

Michael I really like your automated changer setup.

[fishmosy]

I have Ceratophyllum in my ponds and its my plant of choice for floating in breeding tanks and there is some in my shrimp tanks too.   It does have this scary ability ni low TDS water to be shocked into losing all its needles and what a mess that makes!  This week I sold a few shrimp and to hold lots after sorting for sale I put them in coffee jars with some horwort and bubbler... in the morning I had bare stems and shrimp in amongst needles... what a mess.  Had to pick all the shrimp out one by one to bag them.  So yes.  What is it with Ceratophyllum?

 

 

Michael I really like your automated changer setup.

I prefer java fern for this type of thing, absolutely bullet proof.

[kizshrimp]

Actually if you're in a shop ordering Ceratophyllum from the big live plant and food producer it's the only line they expressly provide no warranty on. It's too prone to melting during transport. I've never ordered it from Dave so I wonder how he gets on when shipping it.

What you say about low TDS is interesting Grubs, never checked that but I suppose transport air is low TDS so perhaps there's an answer to be found there? 

[Michael Petro]

It will also loose its needles after a peroxide dip, about 48 hrs afterwards. Dont ask me how I know......