Tank issues with PH/ALK

[Grassy_Nole]

Noticed my PH has been low for sometime now and thought it was my probe. I re-calibrated and still had low PH. So I purchased a new probe. Same results. PH is 7.5. Tested my ALK and it tested low using my red sea kit. Wanted to confirm so I picked up a hanna meter. Its reading a 5.5dkh. Will check phos once I get home.

I using Fritz Salt
1.026
Alk 5.5
PH 7.5
Cal 440
Using a kalk stirrer with ATO

The tank doesn't look bad, but I could tell all was not right. I also noticed all coraline has died from my back glass over the past 12 months. SPS colors are just okay, but looks whispy/frail? Not sure if that makes sense.

 

[saltyfilmfolks]

Not 100% sure the question.

Yes you apperantly need to increase the kalk dose.

 

[Grassy_Nole]

Not 100% sure the question.

Yes you apperantly need to increase the kalk dose.

LOL, i guess there wasn't a question looking back over my post. Im surprised the alk is sooo low. I tested the PH of the stirrer and it was 10+, so I assume the top off is completely saturated by kalk. Should I look into 2 part?

 

[saltyfilmfolks]

Your not adding it directly to the tank then?
Might look into that first.

 

[Grassy_Nole]

Your not adding it directly to the tank then?
Might look into that first.

Confused. I thought you couldn't add kalk direct to saltwater?

I currently dose kalk using an Avast Stirrer

 

[NaH20nerd]

I’ve never been a fan of dosing kalk using ATO. Too many variations in evaporation rates and it’s hard on the pump. It works for some tho...either way your ALK is too low and will allow a larger PH swing as a result. Kalk is a great simple solution so long as your tank demand doesn’t exceed your evaporation rate. If it does, then two-part is usually the easiest solution.

 

[saltyfilmfolks]

You can put kalk right into the tank yes.
Some even use just a bottle with a valve that drips it right in. Def look for a higher flow area to drip into.

Randy Farley did this for decades in fact.
Def check out his article in the stickies in the chemistry forum.

 

[Hitman]

I dose 2 part and Kalk directly into my tank right in front of my return pump. Matter of fact I’m dosing 5 Gallons of kalk every tank weeks @ 2 tablespoons per gallon saturation.

 

[laverda]

I would not increase you kalk as your Ca is high enough currently. I would slowly dose using baked baking soda to bring up the ALK to where you want it. Look for randy’s 2 part recipe to mix or just use the ALk part of any 2 part additive. What is your Magnesium level. It also has an affect on PH.

 

[Randy Holmes-Farley Verified Community Expert]

Confused. I thought you couldn't add kalk direct to saltwater?

I currently dose kalk using an Avast Stirrer

Dry solids, no, although a few people used slurries before the days of two parts.

You can also make a high pH two part DIY (hydroxide based) that has the same pH boost per unit of alk added.

 

[Randy Holmes-Farley Verified Community Expert]

I would not increase you kalk as your Ca is high enough currently. I would slowly dose using baked baking soda to bring up the ALK to where you want it. Look for randy’s 2 part recipe to mix or just use the ALk part of any 2 part additive. What is your Magnesium level. It also has an affect on PH.

While that's a fine plan, the effect on calcium of raising alk by 2.8 dKH using limewater is small (20 ppm) and would not be a problem.