Help!!!!

[bizzleb01]

So, I did my weekly water test and here's what I got
ph 7.4
nitrite 0
nitrate 15
amm 0
alk 2.5
cal 545
I was really worried about the ph so I did another reading about 15 min later and it was at 8.2. I've never had it below 8 before and is this normal for it to jump back up that quickly.
Also I don't think my cal is really that high. My tester is old and I don't think it's very acurate.
I use hardness plus and alkalinity plus about every other day or so. It's a 90 gallon tank and I add a cap full of each. Should I be doing something different to try and keep my water parameters stable. I do weekly 15 gallon water changes.
Thank you for any advice in advance.

 

[tomato clown]

Being they are old, I'd start by get some new testing kits, then comparing the old against the new. You're levels could all be off and you could be causing havok w/o realizing it.

 

[bizzleb01]

Just the cal tester is old

 

[tomato clown]

Yes, you mentioned that. I didn't clarify myself though. Sorry...
I bought a new SW master kit only to see levels similar to yours, only my amm wouldn't move. Test showed it well over 4ppm each and every time. I went and got 2 new kits 2 weeks later only for the 2 new kits to show my amm. 0ppm
Sometimes there is what I call a "Bad Batch" and the tests are just useless.
FWIW though my kits were API and Salifert

 

[groupergenius]

Bizz there are so many variables. What test kits? What calc and alk supplements? Why are you supplementing? What corals?
90 gallon and 15 gallon Water changs weekly IMHO you shouldn't need to supplement.
What part of Florida? Maybe easier for one of us to come by and help.
BTW, Ph would never jump that quick on it's own.

 

[bizzleb01]

Grouper, I'm in St Pete. My calcium and alk test are made by aquarium systems and I have a "master" test kit made by aquarium pharm. When I did the first ph test it came up 7.4. I did add about 2.5 gallons of RO water before I did the second test I think.
I started dosing because my cal was really low and I wanted to promote corraline algae growth. I only have some zoas, mushrooms, a frogspawn, pom pom xenia and a toadstool. I was going to be picking up an acan, but now I'm not sure with my ph being off. .
Thanks for the help guys, I was starting to freak out. Everything looked pretty good so it did seem weird for it to be that off.

 

[bizzleb01]

Oh, and I'm using alk plus and hardness plus.