Don't do what I did / almost killed my fish today

[Rivercats]

I would look into your RO system. If your RO PH is only .2 lower that your tap, something is wrong. i don't use RO in my aquariums, its only for drinking but my tap is 8.4 and the RO faucet is 6.2. All the fish I gett are from the hard water in the area so adding any type of RO in my tanks would surely PH shock the fish.

You are only going to ph shock your fish using RO to lower ph if you use too much RO and try to drop you ph too rapidly. I use RO to keep my ph around the 6.8-7.0 range and my KH and GH around 4. My tap is over 9.0 with Gh 13, and KH 11. I have certain plants that I couldn't grow in my tap water. I've used RO/tap mix for almost a year without issues. I don't remember seeing any stats saying the RO was only .2 lower than the tap. My unit brings my 9.0 tap down to the 7,0 range.
The 8.0 to 7.6 were the ph numbers of his tank before and after the WC in which he used part RO water. Once he runs his ph/gh/kh tests on a new batch of RO water then he will get an idea of what his unit is doing. KH and GH in RO should be 0 (at least that has always been my understanding). PH will vary with each unit and each persons water supply. For me GH/KH are the important numbers, by montioring them (in my tank) and keeping them stable and at the level I want them using RO my PH has always remained stable (at least in my tanks). RO is probably the most commonly used method to safely lower PH/KH/GH in freshwater aquariums.

So all that being said I don't think it was any "one" thing, I think it was just a combination of things in a tank that is still not completely cycled that combined to cause the fish to go into distress.

 

[dwayne.aycock]

Should the PH of my R/O system be lower? What happened is driving me crazy because I just cant put my finger on exactly what happened. Do you think the ferts could have been the problem? Unlikely I know, but the fish were showing signs of distress before I turned the pumps back on and 3 hours later they were fine.Water here in Central Florida is hard with a PH of 8.0. There are both chlorine and cloramines in the tap water due to the warm temperatures. As a matter of fact we are still in the upper 80s near 90 degrees. R/O system is brand new, less than 2 weeks old. Do I need to back flush the R/O already? I still believe the temp was the problem, factoring in chemistry and biology, temperature differential is the only thing that makes scence.
Dwayne

 

[chrismiller21]

I don't remember seeing any stats saying the RO was only .2 lower than the tap. My unit brings my 9.0 tap down to the 7,0 range.

its right below. Even your system drops your PH down 2 full points. His only .2.

I went out and checked the PH of my R/O water. R/O water has a PH of 7.8. My tap water PH is 8.0. PH in my tank is 7.6. So with that being said, this rules out the PH of the R/O water as a source of my kills yesterday. This leads to 2 possible causes.... back to chlorine or temperature swings.

I did add a liquid fert to my tank while my pumps were off, thinking the plants would have more time to absorb it. I used a tetra brand fert supposedly safe for fish. Could this have caused the problem? Pumps were off approximately 30-45 minutes.
Thanks, Dwayne

I would still get the RO system checked. Unless your breeding sensitive fish, have discus or special rare plants, using RO in your aquariums is a massive time consuming headache. If you need lower PH, use driftwood or peat and do it naturally and slowly. I still think something leached into the RO water and/or you have a problem with your system. And I never ad ferts to a still tank. I always dose in the output stream of the filters to disperse it quickly. The fish will swim to it thinking its food and suck in all that iron concentrated in one area

 

[Rivercats]

Test your RO water after you run a batch (ph,kh,gh), keep a log if it helps, it also shows when you change your membranes so you can easily keep the info on hand. I also have a TDS (total dissolved solids) meter for checking my RO water. Honestly I would seriously doubt you need to back flush your unit already. I don't think doing it will hurt at this point but really don't see the point.

What you want to check is your tap water ph and your RO water ph after you run a batch to see what the two numbers compare at. Same with KH and GH. Alot of what I read before getting a unit seemed to say RO's usually drop PH at least a couple points. What is more important is that the GH/KH are coming out 0 on your unit. Those are the numbers that I monitor and want to keep stable at around a 4 in my tank. Then my ph just stablizes at around 6.8 to 7.0. It's the GH/KH that makes your water soft or hard. You want softer water so you want lower GH/KH. I've found 4 or 5 are good numbers for those reading for growing most all plants and seem very good for keeping my soft water fish in. Just remember that your tank water is not going to be the PH/GH/KH number of your RO water. Your mixing the lower RO ph/gh/kh with the higher tap ph/gh/kh to achieve your goal ph/gh/kh number. But again your GH/KH not only affects ph but GH/KH needs to be a stable number to ensure there is proper buffers in the water to keep you PH stable. Stable PH is most important. That is why I monitor my GH/KH more closely than PH.

I couldn't say about the ferts, I don't put anything in the tank if I'm doing a big water change until the change is done and everythings turned back on. I personally don't like putting stuff in the water when the tank is not actively filtering (but remember my 220g has to be turned off for a couple hours when using a water changer due to the amount of water, 100g, that I am emptying/replacing) but again that is just me. I'm sure your changes go much faster.

Honestly I don't think your ever going to know for sure what happened. I think it was truely just a combination of alot of varying factors. Sometimes wierd things happen in our tanks, not too long ago I had plants showing iron deficiency yet even dosing iron I couldn't keep it in a readable amount in testing and the plants would only temp improve with daily iron dosing. Yet when I upped my level of Phosphates (for a totally different reason) a few weeks later, my iron level became stable and testable and my plants showing iron deficiency suddenly corrected and have never has issues since and I only dose a small amount of extra cleated iron once a week. Even aquachem had to speculate on some wierd thing that was probably happening in my water. Point being wierd stuff happens sometimes that most of us just can't explain. Your really never going to know for sure what chain of events caused that to happen, all you can do is speculate.

 

[Rivercats]

its right below. Even your system drops your PH down 2 full points. His only .2.

Before a full system check on a new RO unit I'd rerun PH/GH/KH testing on it. I also use a TDS meter which shows me how efficienct my membranes are filtering total dissolved solids. If indeed the unit is only only lowering ph .2 then there needs to be a system check, but also if that is a correct number most likely other numbers in the RO water will be off which should be checked before doing anything with the unit.

 

[dwayne.aycock]

With no W/C today my numbers are as follows:
NH3/4= 0ppm
PH up slightly from 7.6 to 7.8
NO2 = 0.50 up 0.25 from yesterday
NO3 = 5.0 and stable
tank temp is 80 degrees.

did not feed today but dod add two caps of prime for biological benefits.
I run a 36W UV sterilizer a night as well as air stones in my sump.

Will probably do a partial W/C on Wednesday @ 25% with special attention to PH, Temperature and no ferts.
Dwayne

 

[Botanica]

Ok...so I'm new and don't understand RO systems or any of that...but I do have a relevant question...Should there be nitrites in a fully cycled tank? Is it possible that something unknown fell into the bucket that was toxic at first but filtered out fairly quickly? I've read of simple things such as air fresheners sprayed around an open tank could poison your system. If the tank was cycled fully and is showing nitrites now...could that be an indicator that some of the bb were killed off for some reason? Just doing my best to understand the chemistry...or would it be biology...the science anyway...lol.

 

[bobc4d]

I did the freak out once when I did a water change. I started dumping the last of the 10g in my 36g tank and it hit me. 'did I add dechlorinator?" so I added enough of the declorinator to do the entire 36g . . .just in case. :-\

 

[dwayne.aycock]

Well folks, after a harrowing weekend and a promise the leave the water alone for the next 3 days, mu levels look like this.

Mind you that my tank has been up and running since September 19th.
It now has about 25-30 small fish in a 75 gallon tank with quadruple filtration. I feed the fish very lightly and keek a careful eye on nitrate, nitrite and ammonia.

PH= 8.0 (this is normal for my area).
Ammonia= 0
Nitrite= 0
Nitrate= 0

Tank is planted with live amazon plants that are healthy and green.
Tank temp is 80 degrees

Tank is stable and all fish look healthy and happy

Thoughts?
Dwayne

 

[dwayne.aycock]

Botanica, in a cycled tank there is occasional nitrate as well as ammonia and nitrate. If these levels are monitored regularly as well as requisite water changes, live plant health, correct fish load and no overfeeding, these levels remain low if not a zero. Zero is the goal in a cycled tank; however, steps should be taken (most often water changes to get them back into check).

 

[jlk]

Botanica, in a cycled tank there is occasional nitrate as well as ammonia and nitrate. If these levels are monitored regularly as well as requisite water changes, live plant health, correct fish load and no overfeeding, these levels remain low if not a zero. Zero is the goal in a cycled tank; however, steps should be taken (most often water changes to get them back into check).

I have to disagree with this. In an established cycled tank, there should be zero ammonia and zero nitrite, not 'low' amounts. The only exceptions would be if something happened to change the biological balance (adding a new fish, changing the substrate, removing biological filtration, forgetting conditioner, etc, etc). If there is ammonia and/or nitrite present, then the tank is not fully cycled or something has occurred to change the balance.

 

[dwayne.aycock]

I don't see how what I am saying is any different than what you are saying.

"these levels should be monitored regularly as well as requisite water changes, live plant health, correct fish load and no overfeeding, these levels remain low if not a zero. Zero is the goal in a cycled tank. If these levels are not at zero, then steps should be taken to get them back to zero."
You said "If there is ammonia and/or nitrite present, then the tank is not fully cycled or something has occurred to change the balance."

Not to split hairs, but I think we are both saying the same thing.