High PH in new cycling tank

[nadinemccarthy]

I have a 20 gallon hex tank with a millennium 2000 filter with no filter medium in it along with a current maker and heater. I have a sand bed about 5 inches deep. I got about 10 pounds of non cured rock from my local all fish store who have more salt water tanks then freshwater and a 3 pound piece of cured rock from the same source for the tank. I then got another 5 pound rock from Petsmart to complete my rocks in the aquarium.

They have been in there for about a week now. The PH of my water was 6.8 out of the well. The salinity of the tank water was 1.025 and temperature about 78. I tested for Ammonia on day 5 of cycle and it was off the charts which I interpreted as a good sign that the tank was cycling. However, when I tested the PH yesterday, it is off charts on the test strips. I used two different testing kits. I tried to figure out why and perhaps the rock I bought at Petsmart might be limestone or Conga Rock which I have read might raise the PH of the tank.

I guess I'm asking if this might be the cause and if so, will the tank's PH drop on it's own at the end of the cycle. Will I need to constantly be adding stuff to drop the PH if I keep these rocks in the tank? I'm hesitant to correct any chemistry at this point since the tank is cycling. Any advice for a first time salt water person?

[disc1]

I guess I'm asking if this might be the cause and if so, will the tank's PH drop on it's own at the end of the cycle.
Usually pH goes low during the cycle. My first suspect would be the test strips. They are notoriously bad. But if the pH really turns out to be very high then maybe it's worth looking into how those rocks were made.
Will I need to constantly be adding stuff to drop the PH if I keep these rocks in the tank?

That would be a bad idea. If it really is the rocks then you'll have to cure them out in water until they stop raising pH. That may take a while, but adding "stuff" as you call it to drop pH can have other side effects you may not want.

I'm hesitant to correct any chemistry at this point since the tank is cycling. Any advice for a first time salt water person?

Try to find some way to get a real reading on that water and throw those stupid test strips in the trash where they belong.

[nadinemccarthy]

I actually was using tests that used drops and a strip to compare it to. I've got a seatest kit around here somewhere, so I'll see what that says or get the store to test it for me. I do know I have probably at least 3-4 more weeks at least before it might stabilize.

[ifarmer]

no need to worry about PH at this time while tank is cycling.
I think PH is the least that anyone have to worry about in saltwater.

[nadinemccarthy]

I might just let it run for 4 more weeks and then test everything to see where I'm at. If I have more questions, I'll come back once it has been up a bit longer. Thanks for the thoughts.

[bertoni]

Letting it run for a while sounds like a fine idea to me. I don't know how the pH would become elevated if the tank has a reasonable amount of aeration. I suspect that's just a testing problem.