Will low alkalinity hurt corals?

[ThePurple12]

My alkalinity is perpetually low, at around 5.5. Without daily or several times a week dosing, it will stay that low. Dosing daily isn't ideal for multiple reasons, including messing with the stability. Will my SPS be OK if I just leave it that low?

 

[Saltyreef]

No. Not @ 5.5dkh.

 

[Saltyreef]

id target lowest alk @ 7dkh

 

[stephj03]

How many SPS and what type?
How big is the tank?

It will be pretty hard to avoid daily supplementation with a lot of SPS

Low alk alone won't kill then but you will eventually introduce alk swings when you do water changes as most salt mixes to at least 7-8dkh.

They may find a happy equilibrium at that level but will grow pretty slow at that dkh without dosing

 

[stephj03]

I would double check your test using a different kit first though.

 

[lemonade]

What are you reasons for not wanting to dose daily? That will keep it more stable. I manual dose my 150 daily along with kalk drip and can maintain very stable DKH.

DKh at 5.5 won't hurt the corals but it's not the most ideal. I've had mine stay around 5.5-6 for a month at a time and corals all continued to grow, but colors were so so, and overall just not thriving at an optimal level

 

[P-Dub]

You have received good advice, thus far. Re-test with a different kit. What kit are you using now?

 

[Timfish]

It's not good but how bad it is long term depends on the dissolution rate of sand snyd rock in your system. As mentioned above it really is important to keep it higher. Have you tried dosing bicarbonate in an autofeeder?

 

[ThePurple12]

How many SPS and what type?
How big is the tank?

It will be pretty hard to avoid daily supplementation with a lot of SPS

Low alk alone won't kill then but you will eventually introduce alk swings when you do water changes as most salt mixes to at least 7-8dkh.

They may find a happy equilibrium at that level but will grow pretty slow at that dkh without dosing

The really weird thing is that I hardly have any SPS in my 125 gallon. Here's a picture so you can get an idea:

 

[ThePurple12]

You have received good advice, thus far. Re-test with a different kit. What kit are you using now?

I'm using Salifert. It's running low, so it's time to get a new one anyway.

 

[ThePurple12]

It's not good but how bad it is long term depends on the dissolution rate of sand snyd rock in your system. As mentioned above it really is important to keep it higher. Have you tried dosing bicarbonate in an autofeeder?

That's a great idea! I will definitely try it out.

 

[ThePurple12]

What are you reasons for not wanting to dose daily? That will keep it more stable. I manual dose my 150 daily along with kalk drip and can maintain very stable DKH.

DKh at 5.5 won't hurt the corals but it's not the most ideal. I've had mine stay around 5.5-6 for a month at a time and corals all continued to grow, but colors were so so, and overall just not thriving at an optimal level

Doing that would cause it to swing quite a bit even daily, but Timfish's autofeeder method might be the solution.

Thanks for the input, definitely helps

 

[lemonade]

The really weird thing is that I hardly have any SPS in my 125 gallon. Here's a picture so you can get an idea:

With that few of SPS I honestly wouldn't even worry about it. Only reason I'd be looking to bring it up is if I had some Acropora that I was trying to pull the best growth and colors out of.

The DKH of NSW here in Florida is around 6, maybe even a tad lower. There's nothing wrong with it being that low. However, if you start to get into more Acropora species or more sensitive SPS you might benefit from running it a little higher 7-8dkh. Adding Kalk to your ATO is going to be the easiest way to manage your DKH/Ca at this stage.

 

[stephj03]

How often and what size water changes do you do?

Alk will def drift down with infrequent water changes even with only a few frags.

I experienced this post crash after I took a 2 mo break from doing anything except top off while my morale recovered.

My 3 remaining frags took my alk from 8 to 6.5

 

[ThePurple12]

That must be part of the problem. I do 15% water changes monthly. I'm gonna get something better than a bunch of 5 gallon buckets to hold water in.

 

[Fishfinder]

I don’t see any heavy consumers in the pic. Why not add kalk to your top off? Easy to mix. No maintenance

 

[stephj03]

Kalk is a good call. Add it when you fill up your ATO reservoir and it will get dosed daily by your ATO.

Provided you double check test results and see a low value on a new/different test kit.

 

[ThePurple12]

What's the difference between kalk and baking soda? I'd prefer to stick with baking soda because it's cheaper.

 

[Fishfinder]

Kalk is super cheap. I don’t even know because the cost is negligible. A couple tablespoons in 5 gal and you are good to go

 

[stephj03]

What's the difference between kalk and baking soda? I'd prefer to stick with baking soda because it's cheaper.

Baking soda will only supplement Alk
Kalk will provide balanced Ca and Alk

That's why kalk is the go to for ATO dosing

If cost is a concern search amazon or walmart for pickling lime. Ms Wages is the OG brand but any food grade pickling lime is identical to kalk sold at the lfs