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what is the proper t.d.s. for zebras.I use well water and my tds are high.I had 5 spawns of about 35 fry and only 1 make it so I must have problem I check my tds in the tanks most read over 400 to 600 ppm.So I go a ro/di system and the 4 babys are living longer and growing much faster.The T.D.S.in the same tanks are from 29 ppm to 78.so what is the lowest I can take it.thanks steve

I don't think growing is linear to lower TDS - it's a case of "ideal TDS" will grow better than low or high values. It also depends HIGHLY on what makes up the TDS, and how that affects the fish.

The key factor is that you need something to keep the pH stable, which usually called KH. As long as that is high enough, and there is enough trace elements in the water for the fish to grow nicely, it's unlikely that a higher or lower TDS will make it better.

Note that TDS doesn't tell WHAT is in the water, just how much "stuff" there is in the water (and if you measure with a meter, it really just tells how well electricity can travel through the water). It could be highly toxic at 1ppm, if it's got 1ppm lead in it....

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Mats

Check out your nitrate. They seem very sensitive to nitrate levels....

I known that I got a high level of iron I can tell by the way the tub stains.My ph was high so I got some Neutral Regulator it says to add 1 teaspoon for 10 to 20 gal every month over 2 days I added 5 teaspoons and the ph didn't came.My ph was at lease7.6 the highest the card goes at the time my ph is 6.0 to6.4.The fish are eatting better and are moving around a lot more.My KH around 100 ppm which 3 to 6 %.I'm concern is if I keep using the RO?Di water will it be ok for the Zebas when the water change.My ammonia is 0 nitrite 0 nitrate 0 to 5.0 ph 6.0 to 6.4.Thanks Steve

Hi Steve,
pH 6.0 - 6.4 seems better to me. I have not used RO water, but I understand there is a product called "RO Right"? which adds back trace elements into the RO water to make it 'more nutrious'?

I would get the well water pH tested by a meter that can give you an accurate reading. When a reading goes beyond what your test kit goes to, then you don't know if it was 7.8 or 10.8. Quite a risk with expensive fish.
Cheers
Geoff

Hi all,

400 to 600 ppm

This is a huge TDS, it is equivalent to about 1000microS (1 milliSiemen)conductivity, this would be somewhere in between 10x and 100x the conductivity of their native river. This is why your RO water has done much better, it is directly related to the lower TDS. I have no experience of H. zebra, but for most soft water fish for successful long term maintenance you need soft water with low TDS.

The key factor is that you need something to keep the pH stable, which usually called KH. As long as that is high enough, and there is enough trace elements in the water for the fish to grow nicely, it's unlikely that a higher or lower TDS will make it better.

The relationship between pH and KH (carbonate buffering) is something slightly different. You can have water with a high TDS and low pH, but that is not the same thing at all as acid, soft water with a low TDS. You only need to re-mineralise your water to 4dKH to achieve stability. I would use the recipe here: <http://www.jsctech.co.uk/theplantedtank/RO.htm>

If Bob (Macvsog), picks up this thread he can post all the details of the system he uses to successfully mix RO and HMA water for his Hypancistrus breeding.

cheers Darrel

Hi everyone enjoyed all the imfo.Evidently I must have a high metal content in my well water I know I have a lot iron.I had the water tested but still waiting for the results.Since I got the RO/DI system they the fish are doing great.The 4 babys are a litle over a month old and growing fast.These are the longest that I had the babys live and the adults seen to be growing to.I was concern that using the RO/DI that I was taking all the ninerals and what ever eles out the water so I went to the LFS and he gave me R/O right to ad to the RO water it's got directions to adjust for the soft or hard water.Will take any more info.so I can get right Thanks a lot Steve

Hi all,

that it will not handle unstable pH conditions and will spawn and have viable healthy fry at a pH of 7.8. I lost a tank full of H. zebra in a tank with discus that my significant other was adamant needed to have RO water changes and buffer. The pH wasn't far below 6, but it was more than they could handle at warmer temps.

I'm sorry for your loss, but I don't think that the pH was a cause, possibly more a symptom of whatever killed your fish. Warm water holds less oxygen than cooler water (about 8.3mg/l at 24oC down to about 7 mg/l at 32oC), but this doesn't alter the pH.

There are different reasons why pH may vary, in reality a pH measurement without some measure of the KH value (carbonate buffering) is of little value.

Because pH is a log10 scale ("the negative log of the H+ ion conc."), the change from pH7 to pH6 is 10X less than the change in acidity from pH6 to pH5. Pure water (H2O) disassociates into H+ and OH- ions in a 1:1 ratio (really this should be 2H2O ~ H3O+ (aq) + OH− (aq), but it is the same end result), any addition of acid or base, however small (like CO2 going into solution as carbonic acid), will cause the pH to drop rapidly to a low level. Fish that naturally live in poorly buffered water have to tolerate large diurnal variations in pH (caused by changes in O2 and CO2 levels in the water). It is to limit the swings in pH from the carbonic acid ~ carbonate equilibrium that I suggested buffering the water to 4dKH.

While the relatively large changes in pH in very soft water may not effect your too much, not all pH values or fish are equal, fish that have evolved in naturally highly buffered waters (Lake Tanganyika for example) have little tolerance for changes in pH, here the water is so carbonate rich, alkaline and stable the pH will remain pH8.4, almost irrespective of what happens. If you did add enough acid (and it would need to be a fairly strong acid) to cause this pH to decline by more than a few points, fish death will occur.

My suspicion would be that a lot of unexplained deaths often relate to water quality issues, where slight changes in the efficiency of biological filtration (larger bioload etc.) leads to a fall in the degree of oxygenation of the water and the death of rheophilic fish.

Oxygenation is a fairly complex issue, but with apologies for the cross-post, there is a more complete description here: <http://plecoplanet.com/?page_id=829>.

cheers Darrel

Thanks again for the imfo.I use a 32 gal trash can for my RO/DI system after it's filled I check the PH and KN them ajust with R/O right to get the right KH, the PH stays at 6.4 and after adding R/O right to get the right KH.I do a water change. My temp is 82F and I have 1200 powerhead and 305 fluval in 40 gal breeder tank.After the babys are swimming I move them to a 20 gal tank with the dad then after 2 weeks I but the dad back in the breeder tank.Thanks for the info.Steve PS I'm tring

"If Bob (Macvsog), picks up this thread he can post all the details of the system he uses to successfully mix RO and HMA water for his Hypancistrus breeding. "
I am more than happy to do this if it would be of use?
If the mods are happy i will post it here tonight once i find the doc.

Regards Bob

macvsog23 wrote:If the mods are happy i will post it here tonight once i find the doc.

Not a problem, you might even want to consider grabbing the illustrious first zebra pleco Breeders Award entry. Meantime, feel free to drop me a PM on how to use the quote feature. It will save you some time in quoting replies like you've done above.

Jools

FWIW, mine are spawning (yay) in pH7.2 - I have limestone in the tank to keep the water reasonable. The tank is heavily fed and the pH would be between 5.5 and 6 if it weren't there even with my 40% weekly changes. IME, exact pH is one of the least important factors in spawning these fish.

Hi all,
As Barbie says it is "horses for courses", and I would recommend that every-one uses a method that works for them. I would suspect that both Jools and Barbie have naturally soft water, so in this case the pH is very much a moveable feast, and as Jools says not really very relevant. Personally I have no idea of the pH, KH or GH of my tanks, I know that the KH and GH are fairly low, but the pH measured in the morning, when the lights come on, would be very different from the measurement in mid-afternoon when the plants have depleted the CO2 from the water.

My personal "method that works" is to only measure the TDS of the water, and if it falls below about 70, I buffer it up with a carbonate rich water, and if it rises above about 200 I increase the proportion of rain-water, to keep it in that range. I usually change 10% of the water every day, although I may manipulate both TDS and water changes to induce spawning etc.

cheers Darrel