pH drop with new substrate

[DMills]

I did a complete tear-down about 4 weeks ago. Put in Soilmaster Pro (red; attractice substrate, btw). I retained a bit of the old gravel for bio starter and didn't change/clean the filter media. Light fish loading (ten assorted tetras and a few algae eaters, two clown loach ten shrimp) in a 55 gallon tank. 3W/gallon. CO2. Changed only the substrate.

Problem: pH fell from about 6.7 to about 6 with the new substrate. Nothing else was changed. I've lost two of the algae eaters, and all of the shrimp. The plants are looking pretty good except for the elodea which has turned to mush. I thought that one was impossible to kill!

Any ideas? Should I take steps to bring the pH back up, or will the survivors adapt?

 

[Tom Barr]

Re: pH drop with new substrate

If you did a large water change etc, this will mediate the pH effects.
Do so in the future.

Something else is likely influencing the pH besides the gravel.
Clean the filter good, add more plants, also, if you use a pH pen/monitor, turn the lights off etc before taking the reading.

Generally the pH should tend to neutral if it's due to the substrate unless there's peat etc or some organic matter.

Regards,
Tom Barr

 

[DMills]

Re: pH drop with new substrate

Thanks for the response, Tom.

I've done two fifteen percent water changes, using RO water. For pH, I use the test drops, not a meter or strips. I forgot to mention that my CO2 is on a timer and shuts off when the lights are off.

I wasn't expecting any pH effect from changing the substrate and I was just wondering if anyone else had a similar experience.

I've got the tank pretty full of plants, but will be working to fit some more in. I'd say the area is about 85% covered. Still getting some algae. Interestingly, since I've changed the substrate, I'm getting more red or brown algae. Bristle algae a bit of a problem on plant leaves too.

 

[Tom Barr]

Re: pH drop with new substrate

Thanks for the response, Tom.

I've done two fifteen percent water changes, using RO water. For pH, I use the test drops, not a meter or strips. I forgot to mention that my CO2 is on a timer and shuts off when the lights are off.

I wasn't expecting any pH effect from changing the substrate and I was just wondering if anyone else had a similar experience.

I've got the tank pretty full of plants, but will be working to fit some more in. I'd say the area is about 85% covered. Still getting some algae. Interestingly, since I've changed the substrate, I'm getting more red or brown algae. Bristle algae a bit of a problem on plant leaves too.

Well, certainly sounds like other issues besides the substrate. Namely CO2.
If you only do a few small water changes using RO, then do not have enough CO2, you will get the algae you describe + remove the KH, plants will go after that if the CO2 is too low.
That will inturn drop the pH.

I'd do a larger water change and blend with tap to get about 2-3KH and change larger amounts if you seek to maintain a stable pH as well as add enough CO2. Adding CO2 will drop the pH, so if you compare the pH's, make sure you do so at the same time, generally right before the lights come on.

Also, some pH test kits have a very wide range, pH pens are fairly cheap, 30-50$ and worth it if you want to monitor pH/CO2.

Regards,
Tom Barr

 

[Simpte]

Re: pH drop with new substrate

I may have missed it, but what was the previous substrate? Maybe it was buffering more than the soilmaster does.