gh/tds question

[herrwibi]

Hi All,

Posted a few times regarding my crystal red shrimp and still not having much success. didn't realise my gH test kit was out of date and bought a new one. 

I have a HM- Digital Com 100 it has various settings 0.5 naci / 0.7 442 conversion ppm. At the time with the new test kit i measured the gH and was getting a reading of 7 . My old test kit was showing 5. On the conversion rate 0.5 was showing 120-130 tds and 0.7 160-170 tds. I'm not sure what setting is best.

Showing a high GH i decided to drip with RO for several hours. Managed to get it down to 100-105 0.5 and 140-145 0.7 . gH is currently around 6 now and using the 17.6 for every 1 hardness its roughly around 105 tds . If i understand this correctly the tds won't just be 105 as there will be organics in the water as well so the tds will be higher . I know tds is only used as a guide but going by the information should i use 0.7 conversion ? I am still trying to bring the gh down to 5 so will leave it a week or two and repeat the process.

Any help would be appreciated and hope this all makes sense. 

[sdlTBfanUK]

It sounds like you are going in the right direction and the GH would likely have affected breeding/molting. Aim for the 5 you mention and TDS around 120 (100-150 range). Having reduced the parameters already, that will likely trigger moults and breeding so keep an eye out! The TDS reading from the meter is inclusive of everything in the water and therefore the reading to use.

How is it going generally as I thought you had too many CRS, have they been dying off? The shrimp will reach a point where the environment won't allow any more, maximum occupancy, without some changes (more feeding etc)?

Are the TB shrimp and mischlings doing well?

Luckily for us here in the UK we missed the recent heatwave in europe as those sort of temperatures would likelly have wiped everything out (even at 30 degrees they would have started to die off) unless you can keep the room/tanks cool? 

[herrwibi]

1 hour ago, sdlTBfanUK said:

It sounds like you are going in the right direction and the GH would likely have affected breeding/molting. Aim for the 5 you mention and TDS around 120 (100-150 range). Having reduced the parameters already, that will likely trigger moults and breeding so keep an eye out! The TDS reading from the meter is inclusive of everything in the water and therefore the reading to use.

How is it going generally as I thought you had too many CRS, have they been dying off? The shrimp will reach a point where the environment won't allow any more, maximum occupancy, without some changes (more feeding etc)?

Are the TB shrimp and mischlings doing well?

Luckily for us here in the UK we missed the recent heatwave in europe as those sort of temperatures would likelly have wiped everything out (even at 30 degrees they would have started to die off) unless you can keep the room/tanks cool? 

I thought my crystals were starting to bounce back after seeing 3/4 berried females it's come to nothing and i have no shrimplets. On the other hand with the same parameters gH 7 and a tds around 160 the TB/Mischlings are having a massive baby boom, bigger than last year so i'm slightly confused. Crystals are currently around 145 tds and gH 6 . I don't want to drop the parameters too quick so i'll do another RO water change next week and this is for both tanks. 

I did move to a new remineraliser, i followed the instructions on the back but i suspect that i maybe should of been using the 0.7 conversion and have been adding a higher gh and tds water. I'm going to get my tanks back to 5 gH and see where the TDS settles.  

Added only 7ml instead of 10ml to a 20L container and the gH is showing 4 with a tds of around 85 . It's meant to be 5ml per 10L and should give you a gH 5 and 120 TDS. Going to start going around the 80-100 in my 20l container when doing water changes this way i know the gh will be closer to 4/5.

I know , luckily in Scotland we are always on the cooler side but it's still early days for summer and never know what may happen. 

[sdlTBfanUK]

It looks like youhave itall sorted. If there is evaporation in the tank between water changes that will also affect the parameters so mixing the new water to tds 80-100 and gh 4-5 should help compensate for evaporation as well as gradually gettingthe parameters to where you want them.

Good to hear that the TB/mischlings are doing well!

[jayc]

On 7/24/2023 at 12:24 AM, herrwibi said:

Any help would be appreciated and hope this all makes sense. 

If you are still pondering which scale to use, either 0.5 or 0.7, well ... every time I refer to a TDS figure it is based on 0.5 NaCl (sodium chloride). That's because my TDS meter, and most TDS meters on the market use the 0.5 scale for conversion. (Note: Its NaCl with a lower case L, not i)

What's the difference?

 

• The 0.7 scale is based on measuring the KCl or potassium chloride content of a solution.
• The 0.5 scale is based on measuring the NaCl or sodium chloride content of a solution.
• The 0.5 scale is also referred to as TDS - total dissolved solids.

Note: while this are what each scale is based on, in reality these scales do not measure only the KCl content or NaCl content of the solution, but rather the overall conductivity of all electrically charged ions in the solution, this reading is then converted to give you a 0.5 or 0.7 reading. The true ppm of a solution can only be determined by a chemical analysis, ppm cannot be measured by an EC meter. 

 

The reason your HM- Digital Com 100 has various conversion scales is down to it's application.

EC/TDS meters are used heavily in Hydroponics. At times, you might need to measure the fertiliser content in the water for ... well, growing plants.

 

If you haven't read my article on TDS, go check it out in the https://skfaquatics.com/forum/articles/water-parameters/ section of this forum.

Hope this helps clarify it a bit more and has empowered you with greater knowledge. 😀

[herrwibi]

On 7/27/2023 at 11:11 PM, jayc said:

If you are still pondering which scale to use, either 0.5 or 0.7, well ... every time I refer to a TDS figure it is based on 0.5 NaCl (sodium chloride). That's because my TDS meter, and most TDS meters on the market use the 0.5 scale for conversion. (Note: Its NaCl with a lower case L, not i)

What's the difference?

 

• The 0.7 scale is based on measuring the KCl or potassium chloride content of a solution.
• The 0.5 scale is based on measuring the NaCl or sodium chloride content of a solution.
• The 0.5 scale is also referred to as TDS - total dissolved solids.

Note: while this are what each scale is based on, in reality these scales do not measure only the KCl content or NaCl content of the solution, but rather the overall conductivity of all electrically charged ions in the solution, this reading is then converted to give you a 0.5 or 0.7 reading. The true ppm of a solution can only be determined by a chemical analysis, ppm cannot be measured by an EC meter. 

 

The reason your HM- Digital Com 100 has various conversion scales is down to it's application.

EC/TDS meters are used heavily in Hydroponics. At times, you might need to measure the fertiliser content in the water for ... well, growing plants.

 

If you haven't read my article on TDS, go check it out in the https://skfaquatics.com/forum/articles/water-parameters/ section of this forum.

Hope this helps clarify it a bit more and has empowered you with greater knowledge. 😀

Thank you. Sorry for the late reply. In reference to TDS then my gH is currently around 7 i know this isn't high but don't think my crystals like it this high. I am slowly bringing it down to 5. My question is i know 1 dgh is around 17.9 TDS how can my gH be higher than the tds in my tank? TDS is around 107 in my crystals. I've rematerialized my RO water to 98 tds and a gH of 5 .

[jayc]

5 hours ago, herrwibi said:

My question is i know 1 dgh is around 17.9 TDS how can my gH be higher than the tds in my tank?

Well then, your GH test kit is inaccurate. You don't say which GH test kit is used.

Most GH test kits are only an approximation. 

Take the API GH test kit for example. You drop the test solution into the vial until it changes colour. 

The drop size is inconsistent firstly. And secondly, what if it took 6.5 drops to change colour? It doesn't measure anything less than the whole number. So the measurement is a range ... if the colour changed at 7 drops, then the reading is between 6 & 7. 

What is your TDS reading?

[herrwibi]

7 hours ago, jayc said:

Well then, your GH test kit is inaccurate. You don't say which GH test kit is used.

Most GH test kits are only an approximation. 

Take the API GH test kit for example. You drop the test solution into the vial until it changes colour. 

The drop size is inconsistent firstly. And secondly, what if it took 6.5 drops to change colour? It doesn't measure anything less than the whole number. So the measurement is a range ... if the colour changed at 7 drops, then the reading is between 6 & 7. 

What is your TDS reading?

I'm using NTLabs test kit , my old one expires and I've received a new one . Tds is around 105-110 and this is giving me a gH of 7 according to my test kit.  

[sdlTBfanUK]

I think you may have got the TDS and GH readings a bit mixed. The 17.9 you quote is dGH and equal to GH1, basically they are 2 different ways of measuring GH, the first dGH (d=deutsch or german) and we use the simlper GH in most other countries. The German reading is more precise but a bit too fiddly and un-necessary for our requirements in fish/shrimp keeping etc. It isn't therefore likely/possible that GH7 could be tds 110 even if only 100% GH but that could be down to inaccuracies mentioned by JayC or the TDS meter etc (I have several TDS meters and they all give different readings, though not so way out that it matters for what we use it for). So GH6 would be tds 109 if purely GH was in the water and tds meter was 100% correct and GH test was also 100%. Also bear in mind that tank water and newly mixed remineralised water are likely to be different as there will be 'other' stuff in the water than GH in the aquarium? So you may be quite near Gh6?

The only way the 17.9 could equate 1:1 with GH would be if there was only 100% GH in the water (and nothing else) and that would be extremely unlikely, either naturally or using shrimp specific remineraliser.

[herrwibi]

5 hours ago, sdlTBfanUK said:

I think you may have got the TDS and GH readings a bit mixed. The 17.9 you quote is dGH and equal to GH1, basically they are 2 different ways of measuring GH, the first dGH (d=deutsch or german) and we use the simlper GH in most other countries. The German reading is more precise but a bit too fiddly and un-necessary for our requirements in fish/shrimp keeping etc. It isn't therefore likely/possible that GH7 could be tds 110 even if only 100% GH but that could be down to inaccuracies mentioned by JayC or the TDS meter etc (I have several TDS meters and they all give different readings, though not so way out that it matters for what we use it for). So GH6 would be tds 109 if purely GH was in the water and tds meter was 100% correct and GH test was also 100%. Also bear in mind that tank water and newly mixed remineralised water are likely to be different as there will be 'other' stuff in the water than GH in the aquarium? So you may be quite near Gh6?

The only way the 17.9 could equate 1:1 with GH would be if there was only 100% GH in the water (and nothing else) and that would be extremely unlikely, either naturally or using shrimp specific remineraliser.

 

I don't disagree with you but i'm stumped by this as I've made up a new batch of Ro water and currently reading 95-100tds and a gH of 5? I have ordered an API test kit to double check my results but i am very confused. I know people say you shouldn't chase TDS and focus on gh which is what i'm doing. Just stumped at how one of my tanks can be doing really well and the other one isn't with similar parameters.  TDS meter has been calibrated with 342 solution and was bang on when tested. 

[sdlTBfanUK]

GH 5 would be 5x17.9 which is 89.5 and this would therfore appear to be right with your readings. The GH test is only in multiples of 1.00, so the test could show 5 but it may really be 5.4 or something which would account for the slight discrepancy. 

What GH+ are you using, it may literally just adjust GH, it appears that is the case. Some shrimp GH+ may have additional 'stuff' in them which would mean the Tds and GH may not correlate so closely but from what you have supplied I believe your GH+ only has GH in it?

It looks like your tds and gh equipment are good, try not to get too precise, especially with tds as 1 tds is nothing really. The aquariums water readings will differ due to everything else in there!

[herrwibi]

1 hour ago, sdlTBfanUK said:

GH 5 would be 5x17.9 which is 89.5 and this would therfore appear to be right with your readings. The GH test is only in multiples of 1.00, so the test could show 5 but it may really be 5.4 or something which would account for the slight discrepancy. 

What GH+ are you using, it may literally just adjust GH, it appears that is the case. Some shrimp GH+ may have additional 'stuff' in them which would mean the Tds and GH may not correlate so closely but from what you have supplied I believe your GH+ only has GH in it?

It looks like your tds and gh equipment are good, try not to get too precise, especially with tds as 1 tds is nothing really. The aquariums water readings will differ due to everything else in there!

I'm unsure why ,my tank is showing a gH of 7 with a tds of 105 . I'm using qual drop liquid along with trace one . Not to sure why i'm having so much problems with my crystals as the parameters are within tolerance , Potentially old age?

[sdlTBfanUK]

GH6 would be 107.4 and the GH only shows as complete numbers, 1.2.3.4. etc so it isn't going to be that accurate that you are likely to get both numbers dead on. There may also be something, limestone or other etc that is releasing some GH? What have you got in the tank? This seems quite likely as 23/7/23 you had GH6 in the tank so it looks like it has risen?

If you can mix the water to tds 95-100, GH5 as you mentioned before and do 50% water change slowly (dripper) and carefully that should bring the figures to GH6 and tds 100ish in theory. That will get the numbers closer to perfect and aligned and should help.