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TDS and Prime

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Been trying to reduce the TDS in my shrimp tank. I did a partial water change this afternoon, changing 1 gallon of water in my Fluval Ebi Shrimp tank (7.9 gallon). Before the water change the TDS measured 287, after the water change it was still 256. I used pure RO water with nothing added but some Prime. I'm using a digital tester, BTW.

I haven't measured the TDS in a gallon of RO water with Prime. I will at the next water change, I guess, was thinking someone else may have ideas.

Any suggestions for reducing TDS? I have a mixture of shrimp in this tank, mostly Crystal reds and blacks.

Thanks!
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Yeah, get your RO water to desired GH level and add one drop of prime per gallon. Measure the TDS, that is your "clean" water. Your tank TDS minus your clean water TDS = unwanted stuff.

In my case is DI water +GH + ferts + mosura old sea mud in one tank.... and DI + GH in the other tank.
 

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Opae Ula Crazed.
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If you're using a product to raise GH you are also raising TDS (possibly). I know for a fact Fluval Shrimp Minerals while easy to control how much GH you raise, it will shoot TDS through the roof. Sent me TDS meter off the charts saying 450 with a blinking "times/X 10" . I know you said it was nothing but RO and Prime but for the folks suggesting get your GH where it needs to be, they may be failing to realize(or forgetting) it will also shoot TDS up.

Pretty sure I've tested RO water after adding Prime and haven't noticed any jump in TDS but won't swear to it.

If you do the math it makes sense. You have 8 gallons of water at 287 TDS. You changed out 1 gallon. 287 divided by 8 equals 36 (so, say 36 TDS per gallon). So for each gallon of water you change with straight RO it will lower the TDS by 36. 287 - 36 = 251. Pretty darn close to where you wound up.
 

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Opae Ula Crazed.
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Dadgum Jaime, guess I'll be changing water till the cows come home at this rate!
 

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LOL! Are they having trouble in any way? Cause I'm of the mind if it ain't broke don't fix it. I have some Grade A CRS that are doing fine in 188 TDS. But I've always heard those lower grades aren't as tough as the higher grades. I typically do my water changes and use half RO half tap and don't remineralize (just use Prime) and that keeps my TDS pretty stable where I want it (between 180-190 on that particular tank). Obviously once you get it down you may need to monkey around with it and find out what works to keep it stable when you add water back (like tap/RO, RO remineralized, 3/4 tap, 1/4 RO, that sort of thing). Anything in the tank that could be raising the TDS??
 

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If you're using a product to raise GH you are also raising TDS (possibly). I know for a fact Fluval Shrimp Minerals while easy to control how much GH you raise, it will shoot TDS through the roof. Sent me TDS meter off the charts saying 450 with a blinking "times/X 10" . I know you said it was nothing but RO and Prime but for the folks suggesting get your GH where it needs to be, they may be failing to realize(or forgetting) it will also shoot TDS up.

Pretty sure I've tested RO water after adding Prime and haven't noticed any jump in TDS but won't swear to it.

If you do the math it makes sense. You have 8 gallons of water at 287 TDS. You changed out 1 gallon. 287 divided by 8 equals 36 (so, say 36 TDS per gallon). So for each gallon of water you change with straight RO it will lower the TDS by 36. 287 - 36 = 251. Pretty darn close to where you wound up.
If you are taking water out, you have to put water back in of the proper gH, otherwise you are also dropping your gH as well as your TDS. You want to keep your gH constant, while lowering your TDS. You should always remineralize your water unless you are just doing a top-off due to evaporation.

Now remineralizing will increases TDS of the water. Their is roughly 18 ppm solids per degree gH...so water that has a gH of 4 (a good choice for CRS) will have a minimum of 72 ppm TDS.

Once you get a fairly high TDS number, water changes really are about the only solution to get it down.
 

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folks suggesting get your GH where it needs to be, they may be failing to realize(or forgetting) it will also shoot TDS up.
Lol! You really think I wouldn't know that? Heheeeee! :D

You have to add GH booster to the "new" water, unless you want to dilute your current concentration. So, to know what TDS "clean water" to be used for a water change has, he needs to measure it with the stuff he "wants" in the water. The difference between that and the tank is unwanted dissolved solids, unknown.

For example, one gallon of "clean water" (DI+5dGH+ferts) to be used for a water change in my main tank is 150-160 TDS. Knowing this base TDS I know that if my tank water reads 300 TDS then I have 140-160 TDS of junk.

If you measure just new water + prime, compare it to the tank it's gonna be waaaay different (5dGH itself it's at least 100tds) and then add the GH and ferts to the tank will make impossible to accurately know what is going on.

That is why is good to know what TDS is your "clean" water without unknown buildups.

:)
 

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Lol! You really think I wouldn't know that? Heheeeee! :D


:)
Ummm...no, that's not what I meant. But someone is asking about how to lower the TDS and you brought up remineralizing to deal with GH and did not bring up that it will also raise the TDS of the water. At least, nothing in your posts suggests to someone like me (that's not an expert in all things shrimp related;)) that it will raise TDS. So I just think that both things need to be clarified when they are going to be suggested. I've seen it mentioned time and time again by other posters. Folks have to learn...I'm one of them. I bought some Fluval Shrimp Mineral expecting it JUST to raise GH since that's ALL folks brought up on here is it just does GH, not KH, etc, etc. Nobody mentioned the massive TDS increase. And for newer folks to the hobby such as myself still trying to figure out all the parts of water chemistry that are important in shrimp keeping, I actually prefer things be spelled out;)

So settle down, I wasn't insulting your intelligence and I also wasn't insulting the OP's intelligence as they may already know that as well. I know I had failed to realized what it would do to the TDS because I didn't know any better. It's hard to figure out how everything relates to each other in water chemistry if you're not used to having to deal with it (and loonng out of school, lol). For newer hobbyists I think it needs to be brought up. You never know who will find this thread on a search, months later that's just getting into the hobby.
 

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Yeah, once your tank has a desired level of GH you want to keep it by replacing water with the same level GH (not more as it doesn't evaporate at all or gets consumed enough by plants and inverts).

I learned from another thread that If you change water with a lower amount of GH you could promote early molts (they think they need to molt because it's raining and there is not going to be enough GH to molt again for a while) by causing a drastic drop in the osmotic pressure. So you mix the GH with the new water before the wc.

I believe it makes sense when they say that GH and temp should be matched to the tank.

I'm a newbie with shrimp too, just extra nerd about learning and how to learn.
 

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I was told to use one drop of prime in RO water anyways for peace of mind by the guy who started me into shrimp.

In some areas with very hard water a RO unit without good maintenance can be giving you 30tds, that is what comes out of the tap here in Oakland so our RO units are giving us under 10tds easier. What is in those 10-30 TDS?

I buy water from whole foods dispenser, I always measure TDS and it's always zero for DI and 5 for RO. I haven't seen anyone nor i know about anyone else testing water from where they buy it with exception of us here at TPT. So I assume they can get lazy about changing their membranes and people will still buy it.

It's up to you if you want to use one drop of prime in RO water or not, test your RO water and tell me exactly what is in those remaining TDS. :)
 

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I believe it makes sense when they say that GH and temp should be matched to the tank.

See, I make sure the TDS matches or is close, I don't even test the GH. Not saying that's the right way to do it, that's just how I've been doing it (and also how I acclimate shrimp, get the TDS close before I put them in, granted I don't have $100 each shrimp either!).
 

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TDS is just total dissolved solids, doesn't tell you what it is or it's proportions.
I know what TDS stands for and I know it doesn't break anything down into what each 'dissolved solid is'. But when I deal with MY water and how I mix it (certain parts tap to certain parts RO) then I pretty much know that everything else is going to fall into the same areas as the tanks because it's the similar proportions to what my tanks are set at. When I get the TDS to measure close, everything else falls into place FOR ME. When I was setting up my last tank, I tested the water in the tank, tested the water I was going to put in the tank for changes and once the TDS got close, so did the KH and GH and pH was only about .2 higher when I put it in (would drop in a few hours). I'm not raising low pH shrimp so it's much easier for me than someone trying to raise high grade crystals. And as far as acclimating, there really isn't enough water in the bags I get shrimp shipped in for me to test GH, KH, and PH (using drip tests) so I try to get the TDS close. It's just what I do. Didn't say it was right or wrong, I'm saying I do it differently than some folks and so far it has worked out fairly well for me and the species I keep. Could just be dumb luck. I'm still trying to learn how everything correlates to the other (the relationship in KH, GH, TDS, etc if/when there IS a relationship).
 
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