Found out why my platies died...

[Undawada]

Update on the situation: I still havent been able to go to my LFS to get a KH kit... BUT

I switched my substrate to sand and when I removed the gravel I found something I had forgotten about... I had the bottom part of an UGF still under the gravel.

My tank came with a UGF but I switched to a power filter before I added fish, I guess I must have left the bottom part under the gravel

Anyway, there was a significant amount of waste collected under it, enough to cloud the water when I removed it (of course the fish were in a temporary home while I did this)

I suspect this was the cause of the problem, causing very bad water conditions.

However I never saw an Ammonia or Nitrite spike? Thoughts?

Edited for spelling

 

[skimpy]

The only thought i have that could add to this is that you mentioned you NitrAte is 35 ppm, is that before or after a water change i.e. is that the lowest reading or the highest. The reason I ask is that a high nitrAte level (which is actually Nitric Acid) actually reduces PH over a period of time. If this is the case regular water changes can bring it back up but you may need to do 15% change 3 times a week.

Certainly bogwood lowers the PH in a tank and removing this will help.

I have a low KH in my area and have had problems stabilizing my PH. I have added calcium gravel which has helped raise the KH a little so the PH is a little more stable than it used to be - so I do believe KH is an area to look into.

Finally this post says a lot about water and you might find it interesting to read. HERE

Good luck

 

[Undawada]

My readings were taken just before a water change, so they are at their peak. My test kit says Nitrate is hazardous above 150ppm, so I figured 35ppm was well within safe limits. I could be wrong. I also have live plants.

 

[CFC]

35ppm is a perfectly fine nitrate level, the tank that houses my stingray runs with a nitrate level between 30 and 40ppm and rays are some of the most nitrate sensative fish going.

 

[Undawada]

Bought a KH test kit, I took a sample and got 2 dH...

 

[CFC]

2 is very low and needs buffering, i would suggest placing a bag of crushed coral in the tank or into the filtration system to raise the KH level.

 

[blue_ram]

Anyway, there was a significant amount of waste collected under it, enough to cloud the water when I removed it (of course the fish were in a temporary home while I did this)

I suspect this was the cause of the problem, causing very bad water conditions.

However I never saw an Ammonia or Nitrite spike? Thoughts?

Edited for spelling

When organic waste materials decompose, they don't just release ammonia. Ammonia gets all the attention because it's the number one killer in the new tank. Undigested protein and uneaten food are broken down, and organic acid are produced as a byproduct (along with ammonia). Although your biological filter will convert ammonia into much less toxic substance (nitrate), it does nothing for the organic acid. Fact that you have live plants in the tank may also exacerbate the problem.

pH buffers works like a sponge. As more acid is produced it will continue to absorb until it can't absorb anymore. Until it reaches that point, there will be no change in pH, but after that point, pH will drop rapidly. By doing small to moderate (20%) water change weekly, you're replenishing the pH buffers and keeping the water parameter stable. I really don't like messing with pH; it is a risky business.

Btw, if you are planning to keep the plants, get rid of the UGF. You don't need it or want it. But if you are planning to get rid of plants, then convert it to power reverse flow UGF (RFUGF). I've found that nothing beats a combination of a good mechanical filter and power RFUGF in terms of water clarity (not necessarily water quality, however).

 

[Undawada]

I got rid of the UGF and cleaned the tank when I changed to sand. The explanation you gave makes total sense. Im going to get some coral and put it in my filter to raise my KH anyway.