ph crashes over and over

[flannel]

This is a total mystery. My Mom's tank ph keeps going down to 4.5 - 5.0. I think this is the 4th or 5th round since the beginning of December. It's a 20 gal, running an AC30. No driftwood, no peat. There's 2 danios, 1 tetra, 3 cories and 3 kuhlis left. We've tested our tap water over and over and it is just fine. There have only been a couple casualties miraculously. She uses Prime to dechlorinate. She feeds tetramin flakes and something from Hikari for the bottom fish.

In the beginning the cories started acting weird, laying on their sides and freaking out, that's what alerted us that something was wrong. We took the water in and had it tested at the LFS. PH was 4.5. Figured it was an ornament degrading so we took out everything except gravel, plants and glass. Lots of small water changes brought it back up to normal. For a while. It crashed again. I helped take out all the gravel. Figured that maybe it was coated and that was degrading. Funny thing is, it is natural brown gravel and I don't think it was coated buuut...when I started scooping it out, it was all stuck together, kinda crusty-like and came out in big chunks. It was even stuck to the silicone in places. Mom said it had been like that for a long time (she's not the biggest logical thinker to begin with). She thought it was normal. More water changes and it's back to normal and steady for a while. Then it crashed again so the only other thing she can think of is to put new filter media in. So she did. All of it. I can't seem to get the good bacteria speech to stick for her. But it didn't have a mini cycle and we thought all was well. Well, it's back down to 5 again. Does anyone have any clue what could be causing this? Is there some kind of bacteria that could be giving off acidic waste? That's all I can think of....Help!

[mitchb]

How long has the tank been going for?

You could also put some oyster shells in the ac30 to keep your ph stable but that would be around the 7.0-7.2 level so not sure if that would work for you.

[Diztrbd1]

Have you checked kh/dkh from your tap and tank? If I'm not mistaken this can cause the PH to drop.

couple informative reads:
Adjusting pH in the Freshwater Aquarium - Article at The Age of Aquariums - Tropical Fish
http://www.americanaquariumproducts.com/AquariumKH.html
http://www.americanaquariumproducts....html#khbuffers
Adjusting hardness in your aquarium
Water supply issue in the lower mainland

[neven]

since i doubt your mother would handle gh and kh boosters, i guess crushed coral in the filter will be the way to go here. As for the gravel, she must not have vaccuumed it, ever. Perhaps a sand like substrate would do her better, since it would be much easier for her to vaccuum.

as for water changes, is she doing atleast 30% changes every two weeks?

[taureandragon76]

Gotta be the hardness I would think but then again seeing how you live in Kamloops isn't your water hardness high to begin with? Might be an idea to test the gh/kh levels to make sure. If they are not high enough you will end up with crashes.

[kelownaguy]

Test the kH.
W/O some carbonate in the water,pH will crash w/even minimal amounts of CO2 or acidifying pollutants present.

Keep in mind that the nitrifying bacteria consume kH,so regular replenishment of the carbonate/bicarbonate content is necessesary.
Normally,regular water changes are all that is required,not chemicals,unless you are using RO water.

Once the pH is that low,nitrifiction almost ceases,AFAIK.

[Morainy]

I'm just wondering if the crusty substrate is due to overfeeding and lack of gravel cleaning? If so, maybe rotting organic matter (food) is lowering the kH and pH?

I would wash the gravel or replace it, and switch the AC 30 to an AC 50, and perhaps use some charcoal in the filter. I'd also add some Equilibrium to the water changes if your water is soft. However, I don't know what water conditions are like in your area; perhaps that's not necessary.

[Rastapus]

Have you checked kh/dkh from your tap and tank? If I'm not mistaken this can cause the PH to drop.

couple informative reads:
Adjusting pH in the Freshwater Aquarium - Article at The Age of Aquariums - Tropical Fish
http://www.americanaquariumproducts.com/AquariumKH.html
http://www.americanaquariumproducts....html#khbuffers
Adjusting hardness in your aquarium
Water supply issue in the lower mainland

Thanks John,
This thread put a smile on my face, looks like almost everyone is accepting the low hardness issue.

[flannel]

Thanks for all the suggestions. The tank has been running for maybe 4 years. 2 years in Penticton, it was brand new, then 2 years ago mom moved to Kamloops to live with us. I helped all the moving stuff and aside from some light related green water right after the move it has been perfect.
I do believe our water is a bit harder here to begin with, it's never really been an issue, so it wasn't something we checked. I will clarify about the gravel...she was vacuuming pretty regularly but it was getting to be so much of a chore that she took almost all of it out over a year ago. All that was left was just a smattering, basically enough to give the bottom a bit of color. after that, she would just give it a big swish so the filter would grab most of it (which was usually not much stuff) then just rinse the filter later in the day. That seemed to be working really well. It was the best compromise I could come up with without just taking over and looking after the tank for her. It's a bit unorthodox but she's 70, so we do whatever we can to help her be independent. I really wonder if the gravel being stuck together was some kind of bacterial thing going on. It was just so weird. I even gave it a big rinse after to see how dirty it was and basically nothing came out of it but it would still stick together.

We will get the gh/kh tested and I'll do some reading at those links to see if anything rings a bell for me. Thank you everyone for all your help!

[kelownaguy]

I'm just wondering if the crusty substrate is due to overfeeding and lack of gravel cleaning? If so, maybe rotting organic matter (food) is lowering the kH and pH?

I would wash the gravel or replace it, and switch the AC 30 to an AC 50, and perhaps use some charcoal in the filter. I'd also add some Equilibrium to the water changes if your water is soft, because raising the hardness might help the pH stay more stable. However, I don't know what water conditions are like in your area; perhaps that's not necessary.

Equilibrium won`t help.It raises gH not kH and it is not very good at that either.

It is about 40% potassium sulfate which contributes to neither kH or gH.