New system

[Fred]

I recently started a 250 gallon system.  Previously, I had little trouble starting a smaller 55 gallon system so I followed the same steps.

It's been a few weeks and I've been unable to get my ammonia levels down after bringing them up to 3ppm.  After some more testing I've concluded my PH was very low.  I believe my test kit was bottomed (API kit) at 6.0 PH.  I failed to realize that my PH was actually much lower.  I've ordered some PH calibration solution to confirm PH on a PH test meter.  When I tested with my meter, it showed 4.4PH and I incorrectly assumed my meter was off.

I'm using tap water filtered through a stealth RO unit.  I will be testing the water out of the RO unit but this low of a PH surprised me.

Right now I'm slowing adding lime to bring the PH up to a reasonable level to cycle 7.0 or so.

Has anyone else had a situation like this?

[Joel Berg]

That is very acidic, here in Salt Lake, our water is very basic so I recently had to bring my pH down

[Alex Veidel]

Is there anything currently living in your system? If not, you can probably bring that pH up a little faster than normal. And you can keep it a little higher (7.8-8.0). The bacteria like it a little more on the basic side of things :)

[Fred]

No, just a few tomato plants which surprisingly didn't seem to mind the PH.  I'll post more details after I test my RO water, but I suspect this RO water will be in the mid 6 range.  I did add a half gallon of bacteria starter that was past the expiration date.  I wonder if this could have so drastically lowered my PH.  The entire system is plumbed with PVC and my media is expanded clay so I'm a little puzzled as to the high acid PH.

I'm debating dumping most of the water and just starting over.  Some water wasted but I'd rather have a clean start.

I did construct a cone bottom for a swirl filter using some plastic parts and some sheet metal screws but I can't see any of these having such a large PH drop.

Alex Veidel said:

Is there anything currently living in your system? If not, you can probably bring that pH up a little faster than normal. And you can keep it a little higher (7.8-8.0). The bacteria like it a little more on the basic side of things

[Harold Sukhbir]

Hi Fred,

Sorry you had to wait so long to find out about your Ph. Shoot for Ph 8 and 80F temps if possible. With RO you'll have to keep a keen eye on the carbonate levels as you know.