Ph in the gutter... ideas?

[phreeflow]

Just add some crushed coral to keep things stable and buffered

 

[duanes]

It’s a 150g - there was one pleco living in there for 3 weeks eating 1-2 massivore per day. I did maybe 1-2 little water changes, not my weekly 50% as there was just the pleco.

80deg

2 - fx6
2 - EMP 350’s

I usually don’t check ph, I was acclimating the black arrow in there and made the discovery...

The pic is water just now...

Tap ph far left - 7.6
Tank 5.0-6.4
Nitrate - 5.0-10.0 ppm

I have done two water changes one Monday before fish came 25% and one Tuesday 60% after discovering ph so low... before the 25% change there were 40-60ppm nitrate... is this a result of no water change festering nitrates?

A lack of water changes (leading to 40-60ppm nitrate) would do this.
pH drop and high nutrient load usually coincide.
But it could also be that "if" filter media has been allowed to gunk up over time, the filter could be spewing nitrate, and contributing to pH drop.
And although the tap pH is in the 7s, this does not automatically mean the tap water has sufficient alkalinity (buffering capacity) to maintain a stable pH .
If carbonates are low, and are quickly used by nutrients in the tank, it usually means a much more frequent water change schedule may be required to hold the tank at equilibrium.
Coral sand sometimes helps, (is the Coral Sea in your tank actual coral sand (aragonite) it looks to me (?) to be the inert type, (looks can be deceiving) and as mentioned you might be better off with a crushed coral as substrate to help buffer.
This can be done "expensively" with aragonite or can be done inexpensively with crushed oyster shell, of even ocean sea shells in a sump.
Where I now live, my tap water is desalinated sea water (almost RO) so buffering capacity is low, and I supplement with rain water (also low buffering) so I cram old sea shells under the flow from tank to sump to add buffering.

I also use ocean beach sand as substrate comprised of partial shell and coral bits.
As a temporary fix, baking soda can be added to water change water, but is quickly used up, unless it is added with every frequent water change.

 

[dr exum]

Very helpful thanks!

It’s not a terrible ph, but seems pretty low... and did not change with the two water changes I did..

Gonna crack open an fx6 , sounds likely it’s spewing nitrates

Cause there’s was only one pleco in there... I slacked water changes...

 

[squint]

Gonna crack open an fx6 , sounds likely it’s spewing nitrates

One "feature" of canister filters is the ability to collect months' of waste and partially negate the benefits of any water changes you do...

 

[DN328]

I have relatively big pieces of malaysian driftwood to the tank volume. Driftwood also lowers Ph.

 

[dr exum]

I have relatively big pieces of malaysian driftwood to the tank volume. Driftwood also lowers Ph.

I’d figure with the wood - it’s just the carib sea gravel , PetSmart rock and the two plastic Fluval plants...

I cleaned one of the fx6’s - gonna Check the ph on all tanks, I figured I could slack off on water changes due to the enormous filtration and one pleco eating 1-2 pellets a day... ??

I suppose 6-6.5 is not terrible...