Fish loss problems.

[Bedlamer]

Does serious decomp actually lower pH?

I think mRoy nailed it. The most famous example of that are peat bogs. The decomposisition of the detritus lowers the pH then inhibits bacteria. In Europe there are a few places where human remains have been discovered in peat bogs from a thousand plus years ago. Even their leather clothing is intact.

[Bedlamer]

these are the old whisper 2 so you pour carbon into the floss sleeve. and yes, I throw away both the floss and carbon when I change the filter.

From what I'm reading, unless there is a separate bio-media cartridge or a bio-wheel type of thing that is retained--if you throw away the entire cartridge you have thrown away most of your bio-filter--especially if you are running tanks without substrate. The only beneficial bacteria left would be in the bio-film on the surfaces of the tank and the plants--which would not be a lot of surface area compared to say 3" of substrate/some sort of bio-media/live rock (like used in SW systems) etc. And the most dense concentrations would have grown on the filter cartridge because of the water flow. Years ago I ran a 15 gallon tank with 3 goldfish (1 L & 2 M) and a AC 50 with sponge and carbon. So I was over stocked to start with. I did have about 1.5 " of gravel. Which I vacuumed every week when I did a 80% water change. I also rinsed out the sponge with tap water and changed 100% of the carbon every week. I thought I was doing a good job taking care of my fish. About 4 days after the WC I'd get cloudy water then fish acting distressed. I'd take a water sample to the LFS and they would tell me my ammonia was high. Then they would sell me ammonia-rid chip media stuff. In retrospect I wish they had just told me to stop cleaning my filter, or at least do it infrequently, only swap part of the media at a time, and rinse the remaining media in de-chlorinated water. I've stopped using carbon routinely in my tanks. I've mod-ed some filters to remove carbon and add back in some ceramic bio-media. Is it possible to cut open your cartridges, toss the carbon and re-stuff it with bio-media? Then just rinse in de-chlorinated water to clean them?

[Fancyfish]

From what I'm reading, unless there is a separate bio-media cartridge or a bio-wheel type of thing that is retained--if you throw away the entire cartridge you have thrown away most of your bio-filter--especially if you are running tanks without substrate. The only beneficial bacteria left would be in the bio-film on the surfaces of the tank and the plants--which would not be a lot of surface area compared to say 3" of substrate/some sort of bio-media/live rock (like used in SW systems) etc. And the most dense concentrations would have grown on the filter cartridge because of the water flow. Years ago I ran a 15 gallon tank with 3 goldfish (1 L & 2 M) and a AC 50 with sponge and carbon. So I was over stocked to start with. I did have about 1.5 " of gravel. Which I vacuumed every week when I did a 80% water change. I also rinsed out the sponge with tap water and changed 100% of the carbon every week. I thought I was doing a good job taking care of my fish. About 4 days after the WC I'd get cloudy water then fish acting distressed. I'd take a water sample to the LFS and they would tell me my ammonia was high. Then they would sell me ammonia-rid chip media stuff. In retrospect I wish they had just told me to stop cleaning my filter, or at least do it infrequently, only swap part of the media at a time, and rinse the remaining media in de-chlorinated water. I've stopped using carbon routinely in my tanks. I've mod-ed some filters to remove carbon and add back in some ceramic bio-media. Is it possible to cut open your cartridges, toss the carbon and re-stuff it with bio-media? Then just rinse in de-chlorinated water to clean them?

That is a good point. I'm running mostly bare tanks now with some plants. I used to run mostly undergravel filters with a lot of gravel and hang on tank filters. Changing out the cartridges as they clogged. None of my tanks are undergravel right now. So hmmm will have to think about this.

[Fancyfish]

Reading the posts and looking stuff up we've decided it is 2 problems. Both caused or steming from the low ph. Since the ph drops so low, when I do a water change the ph rises and causes an amonia spike which stresses and kills the fish. And if the ph drops too low, the water becomes too acid which stresses and kills the fish. Since my alkilinity is so low, I don't have any thing keeping the ph from dropping. So I'll get a fancier test kit to verify this theory of low ph and try and figure out what I need to do to keep the ph from dropping.

Thanks!

[Bedlamer]

For the pH I'd say just a regular weekly schedule of water changes should keep adequate amounts of naturally occuring buffers in your tanks, without it all getting used up.

[Bedlamer]

And if you, like most people find doing WCs a chore, and you do not already have one--a Python-type hose attachment for siphoning/filling your tanks is worth its weight in Purigen.

[aquabee]

Best of luck! Keep us posted.

[aquabee]

And if you, like most people find doing WCs a chore, and you do not already have one--a Python-type hose attachment for siphoning/filling your tanks is worth its weight in Purigen.

+1! yay Purigen!!

[Mzungu]

Just a side note, but be careful also adding newly-bought fish to established tanks without quarantining first. Some of the crashes could be the result of adding sick fish that appeared healthy when you bought them.

Hope everything goes well from now on! :)

[Fancyfish]

To update everyone it's been a couple weeks now and what I am finding is my ph drops over the course of a week. I lost one more tank of fish (5 gupies) to this. It appears that I need to to water changes once a week to keep the ph at an acceptable level. I had a 10 gal tank of 5 adult guppies that started hanging at the top of the tank and sure enough, checking the ph and it was 6.0 or less. Did a water change and brought it up to 7.0 and the fish are fine. I just find this to be a weird problem to have in Houston!

thanks for everyone's suggestions!