I have a 6.5 gallon high tech, Co2 solenoid injected, aquasoil Amazonia, EI dosed heavily planted tank with Boraras and I've been watching my PH with a meter the past week to fix a problem I've been having.
I noticed the PH of my tank water in a cup outside the tank (without Co2) is 7.0 (same as the RO water I use), during the day the 8 hour injected Co2 lowers that down to 6.05 (Co2 comes on 30 min before lights off and turns off an hour before lights off).
Between lights/Co2 off in the evening and in the morning when I wake up the PH has dropped from the Co2 lowered 6.05 down to 5.20s! When the light comes back on the PH rises again. I know this is because the plants release Co2 at night but my drop checker doesn't change at all over night to reflect this happening. The fishes gills are moving more rapidly in the morning too and sometimes they are gasping at the surface (plenty of rippling flow and I have a surface skimmer). Turning on the light almost immediately solves the problem cause plants start using up Co2 instead and fish start breathing slowly again. I'm already using a solenoid what else can I do to keep it from going this low? I've been experiencing nitrite mini spikes (low ph affecting bacteria maybe) along with the lower ph swings the past few weeks and it's been exhausting the crap out of me with lots of 30-50% WCs (carry 5 gallon tubs back and forth with my car) and even drove home from work one day to save all my fish. Normal for ph to drop this low after Co2 injection at night?
Any thoughts? Thanks
What is your KH level? Low level could cause PH swings. When you say plenty of ripping how much are you talking? You should be off gassing most of the night causing almost all to be gone by the time the co2 comes back on. How long is your co2 off for? I would either use a airstone or another powerhead ripping the surface pretty hard after co2 is off. This will help off gas the co2 more.
Its not the plants releasing co2 at night but its the off gassing causing the co2 to leave the tank. The more surface movement the more will off gas.
Also your aquasoil Amazonia will try and buffer your ph to what level I am not sure as I do not have experience with it so hopefully others chime in but this could be causing your PH to swing like this especially if you have very low KH. What is your KH level?? Remember the less it is the more it can cause ph swings.
Haha sorry I meant surface rippling / agitation. I run two small eheims and have a surface skimmer AND run a AC adaptor computer cooling fan across the top 24/7 and have an inline chiller so no problem there.
GH is between 3-6
KH is always 0 cause of the aquasoil removes it.
I've read as much as I can on this forum about worrying about KH, PH and CO2 injection and looks like the consensus leans toward not over worrying about it and the GH minerals and KH levels matter more but some people agree or disagree with use of crushed coral or baking soda cause they cause problems with PH swinging and CO2. Such a messy balance.
My Light/CO2 schedule
Co2 on at 11:30 am (any earlier fish start gasping cause it's a small tank)
Lights start ramping on between noon and 12:30 pm
Co2 reactor off at 7:00 pm
(Switching from reactor to inline ceramic atomizer this coming week because of issues with Co2 being trapped in the reactor over night and insufficient flow, but I "burp" the leftover co2 out of the reactor ever night now and this doesn't stop the PH drop.)
Lights start ramping off from 8 to 8:15 pm
So the lights are off from 8:15 pm till noon the next day. Does seem like a while but I'm afraid to run the light longer than 8 hours cause I've been slowly winning a rhizoclonoum algae battle and don't want to bring it back. I'll emergency turn one light on ignore fish are gasping and it solves it then i turn into off after an hour till lights on at noon
Recent PH meter results (calibrated in a Lab at my work):
Monday through Friday:
6.7 PH before co2 came on
5.5-5.7 after co2 ran for 8 hours
6.05 PH before CO2
(Cleaned canister filters-tank water only rinsed and new tubing added fresh small pyrogens bag and nothing else but a water change to the tank)
PH dropped to 5.5 during the day
Woke up to PH 5.27
PH 5.17 drop as day went on
Tested PH meter on clean RO water and seemed to work ok. Will recheck in lab at work tomorrow but I'm pretty sure the problem isnt the meter.
I've never seen it drop this low.