Dkh and Ph dropping

A month ago I did these tests:
Ph 8.3
Calcium 400 ppm
Alk 89 KH
Magnesium 1280 ppm
Nitrites 0 ppm
Nitrates < 1 ppm
Salinity 1.020
Temp 78-79

I have slowly brought my salinity up to 1.026 in order to try to raise alk but it is still at 89.5 ppm or 5 dkh. My Ph is now 7.8 !! I only do a 20 or 40% water change once a month.

I use Oceanic salt which I've heard will keep alk too low. Anyone else had this problem. What about using a different salt?

Rather than dose, I want to solve the cause of the problem.

 

Do you use a glass top? Oceanic, at least last time I tested it wasn't that low on alkalinity so I can't imagine that is the issue... What do you have for livestock? What coral if any do you have? What test kits are you using?

 

I have a plexi-glass top over a Biocube 29 but I have a fan blowing air under it constantly and there are several openings for air to come out. I can feel the air blowing out the openings. I have 2 fish one is a small Yellow Clown goby the other is a sixline. I put a 3 inch diameter green plate coral in their 1 week ago. No other corals.

 

If you suspect that your salt is causing your lowered Alkalinity, you may want to try other brands for reef aquariums that have a proven higher buffering capacity. Look into Reef Crystals, Tropic Marin or TM Pro Reef and see if a water change with another brand helps stabalize/boost your alkalinity.

 

you should get some buffer
and dose accordingly

 

Use some baking soda to raise your ALK. Use the calculator on the site to figure out how much you need.

 

If you have any calcifying life in your tank you will have problems with ALK dropping. Coraline Algae will use up alk (as well as calcium but alk is used up a lot faster).

If you want to keep a reef tank you will be either doing lots of water changes or dosing calcium and alk to keep them close to nsw levels.

 

Yep its just one of those things most people have to dose. The more established your tank gets the faster it will use it up.

 

Do you have any stony corals? How old is the tank? As said above it's just something that comes with reefing. I add about a table spoon of sodium carbonate every few days.(your tank will vary) You can use baking soda from the grocery store or soda ash from bulkreefsupply.com. I've been using kent marine dkh buffer but it's all about the same.
If your corals are drawing out water elements at a good clip... water changes won't always replenish needed trace elements fast enough.