New to Reef Water Chemistry

[SFKINNC]

Haven’t dealt with SW chemistry in about 30 years. Back then, I don’t remember ever having water problems after cycling the tank.

Now: New tank (first reef ever). Biocube 32 with dry “live” rock (about 40 lbs.). After adding rock there is between 18 and 19 gallons of water in the tank
Cycled tank. Added:
1 Leather coral
1 Firefish
3 Turbo Snails
3 Nassarius Snails.

Lots of red algae — stringy — probably cyanobacteria I think.
Also lots of diatoms and green algae which the snails seem to be working on.
Changed 5 gallons on Dec 8 made with distilled water.
Water Chemistry numbers:
Salinity 1.o232
GH 180
KH 143.2 PPM
PH 7.5
NO2/NO3 ZERO
Ca 360

Question: How to raise pH? And how to raise Calcium? Do the rest of the numbers seem good? Do I need to test for anything else?

 

[Randy Holmes-Farley Verified Community Expert]

The GH (general hardness) can't be 180 ppm calcium carbonate equivalents.

Is that KH? (alkalinity?)

 

[SFKINNC]

Thanks, Randy. You’re correct; the test strip I used only gives accurate GH readings for fresh water. So that false reading was due to operator headspace.

Repeated my tests. Results are:
Calcium (Ca2+) 360

KH (Carbonate Hardness)
Test strip 80
Liquid test kit 8 or 143.2

PO4 is hard to understand: when I look at the test tube from the side and try to match the color chart, it looks like o.25, but when I look down through the top of the test tube it looks like 5.0! Boy am I confused.

pH between 7.5 and 8.0

Posted a photo of tank showing algae growth.

 

[Randy Holmes-Farley Verified Community Expert]

GH is not useful in seawater, if if you could measure it as it is a mix of measures for magnesium and calcium.

Don't worry about the pH yet. It is a secondary concern.
Forget the alkalinity test strip and focus on titration tests for alkalinity. If the liquid test you used involved adding drops to a color, then that's what you want, and 8 dKH is fine. What brand kit?

The calcium is a bit low, but may be from your salt mix. What salt mix and what salinity (measured how?).

 

[SFKINNC]

Thanks for the quick reply.

Test kit is API reef master kit.
Salt mix is Instant Ocean Reef Crystals. I had used Instant Ocean many years ago, but this batch has me concerned. It was supposed to make 50 gallons but after making only about 35 gallons it is nearly gone!
Salinity a little more than 1.023 (estimate 1.0232) measured with a swing arm hydrometer after bubbles have been shaken loose.

 

[Randy Holmes-Farley Verified Community Expert]

If you raise the salinity to 35 ppt (sg = 1.0264), your calcium will rise to about 410 ppm, which is better.

 

[SFKINNC]

Thanks. I always was told that 35 ppt (1.026) was the upper limit for salinity and, therefore, to keep the specific gravity around 1.023 so there would be a margin of safety to allow for increasing salinity between top-offs. Or have I grown up believing old “fish stories”?

 

[Randy Holmes-Farley Verified Community Expert]

Thanks. I always was told that 35 ppt (1.026) was the upper limit for salinity and, therefore, to keep the specific gravity around 1.023 so there would be a margin of safety to allow for increasing salinity between top-offs. Or have I grown up believing old “fish stories”?

Well, it's certainly not the upper limit (IMO). IMO, it's an appropriate target and is the overall ocean average.

Corals and fish thrive at much higher ssalinty.

 

[SFKINNC]

Thanks. I always was told that 35 ppt (1.026) was the upper limit for salinity and, therefore, to keep the specific gravity around 1.023 so there would be a margin of safety to allow for increasing salinity between top-offs. Or did I grow up believing in old “fish stories.”?

 

[SFKINNC]

Thanks. I always was told that 35 ppt (1.026) was the upper limit for salinity and, therefore, to keep the specific gravity around 1.023 so there would be a margin of safety to allow for increasing salinity between top-offs. Or did I grow up believing in old “fish stories.”?

Sorry! I double posted

 

[SFKINNC]

Thanks for the advice.