why's my pH so low??

[fishface]

i've pretty much finished cycling my tank...or so i think. ammonia is 0, nitrite is 0 and nitrate is barely perceptible but i was wondering why my pH is still at 7.7. is it as simple as boosting with baking soda or are there underlying issues? oh yah, check this out, i checked my ca with a hagen test kit and it measured just over 600 could this be possible? the salt i've been using is coralife marine grade scientific salt if that helps any.

can anyone spare me some knowledge here? please

[Aquattro]

Your calcium is not over 600. Have a second test kit, preferably not Hagen, provide a second opinion.
As for pH, how are you measuring that?

[rickjames]

Have you done any water changes since the cycle? The process of the cycle will lower the pH of your aquarium, so best to a large water change to get the pH up (if 7.7 is indeed the value).

[trilinearmipmap]

I is possible that the Ca is very high due to excessive addition of Ca supplement, this would lower the Alk by precipitating out CaC03, this would give a low pH.

Have you been adding any calcium supplements?

[fishface]

- haven't added any supplements
- pH reading via caliberated pH meter
- and yah, my plan was to go get a salifert Ca test kit today cause that is what i think is with my Ca issue.

so perhaps i should do a fairly substatial water change you figure? how much is that? with my planted tank i do weekly large (50%---60%) but i would think that would be too much for this tank huh? so 20-30%? what do you guys think?

also, thanks for the input!

darryl
ps do you use a kh kit for testing alkalinity?

[fishface]

just tested with the salifert Ca kit and got 420ppm which i think is a good number. gonna do a 25% water change so we'll see what it does for pH

[Doug]

Many reasons why the ph is lower than normal. First I would not worry to much at this time. Water changes are always good, but remember ro water has a low ph and some salt mixes are still under 8.0

In a mature tank the ph rises during the day when lights are on and drops during the night. Oxygen/co2 relationship, the same as fresh water. I dont assume your lighting much yet either.

Also without the specs of your system, its harder to tell. Sumps being fed from large overflows and drain pipes, greatly raise ph values. As do large skimmers.

One can also raise the ph by adding airstones, {not always the best in a salt tank}, or even powerheads, pushing water from the bottom to the surface, creating a boil.

[nanosteve]

What's your water prep routine? RO water has very low pH (mine is 7.4-ish), and should be areated (I have a powerhead and an airstone in overnight), then sea or reef buffers added (I usually let it mix for a day again), and then salt mix if necessary.

[Rikko]

A KH test is fine for testing alk - I think what a KH test measures makes up like 98% of alkalinity or something like that. I use both a Hagen and Salifert kit and get the same results.
The one thing about the Hagen kits is that you get results in ppm, which isn't that used.. I think the conversion from ppm to dKH is to multiply ppm by .0155.. Google should have it.

[fishface]

hey all!
my pH numbers seem to still be on the low side but can someone tell me if they are still acceptable?

Ca-490 ppm (no supplimentation)
KH-9.3
SG-1.025 (too high?)
pH morning-7.8 evening 8.0
no3 and po4 barely perceptible
added another power head for surface circulation

been using ro/di water for changes (25% monthly) and top off, and raising alk with baking soda but just picked up some kents coral builder last night (better?). anything else i should be taking in consideration or does all seem fine?

as always...appreciate your input...
darryl