Question on Ca, Alk, Coralline Algae and Coral Growth

[User1]

I am currently dosing 18 ml of ALK a day in my 210 gallon mixed reef to maintain a reading of 8.1 - 8.2 according to my Trident. I've checked manually with Hana kit. I am not dosing CA. It is holding steady at 425. Mag is holding steady at 1345. I'm wondering why I don't have to add CA and could this stall coral growth?

My upgrade uses 150 LBS of dry Pukani rock and over the past 18 months the coralline algae is really starting to cover the rocks. I'm assuming it is using CA and wondering if it is using more than my corals. Which then got me thinking I'd assume I'd need to dose CA but it doesn't seem like I need to. ALK was pretty obvious once the Trident was running because I can see it decline over the course of a week. CA - just seems to be doing its thing so was wondering.

I do a 15 gallon water change maybe twice a month using instant ocean reef crystals. I'm using ESV 2 part but only dosing ALK as I noted above. Maybe nothing and normal but figured I'd ask if I should add a small amount of CA or just let the tank guide me when it is necessary. Mostly soft corals. Few SPS such as Monties and a few unknowns. Crappy picture - sorry - but you can see the Coralline blotches starting to spread an all rocks.

Thanks for any info, tips, tricks, etc.

 

[Justfebreezeit]

Have you tried adding the equal amount of calcium and seeing if the calcium actually rises?

It's somewhat surprising you haven't had to add calcium yet. Maybe randy will have an idea.

 

[Mykawl]

Following beautiful tank

 

[flsalty]

Is it possible you just don't have enough in there to make a big dent in calcium? You have 210 gallons and some small frags. IORC is supposed to mix at 490 and you get 425. Maybe the water changes are keeping up for now.

 

[User1]

Have you tried adding the equal amount of calcium and seeing if the calcium actually rises?

It's somewhat surprising you haven't had to add calcium yet. Maybe randy will have an idea.

I've not, no. Good idea and I'm sure I can start with a lower amount and see if it increases, decreases, etc. Thanks.

 

[User1]

Following beautiful tank

Thanks. It has a long way to go. Dry Pukani is taking a long time to mature - more than I thought. The upgrade is only 18 months in to be honest. That is what got me thinking that maybe I should be adding it due to the coralline growth. I even added 2 maximas last month once I was ready.

CA still holding steady - go figure.

 

[User1]

Is it possible you just don't have enough in there to make a big dent in calcium? You have 210 gallons and some small frags. IORC is supposed to mix at 490 and you get 425. Maybe the water changes are keeping up for now.

Yeah - that is actually a great point. I've not tested my make up water but I do 15 gallons about every two weeks. I'm positive on the gallons because I use 5 gallon buckets Well, give me + or - a gallon but it is a pretty close number anyway.

They are all small frags for sure. Just test corals. The soft corals have been around and moved from my 40 breeder. Also the RBTA's are from that tank.

 

[User1]

And thank you all - appreciate the suggestions and feedback.

 

[Silver14SS]

Have you checked Ca and Mg manually as well, or just the Alk?

 

[madweazl]

If you're using something like Randy's 2-part for alkalinity (or BRS; soda ash), 18ml isnt much at all (approx .1 dKh/day). You'll only use about .6ppm calcium/day if my math is correct.

 

[User1]

Have you checked Ca and Mg manually as well, or just the Alk?

Just the ALK. I was going to run through the Ca and Mg this week.

I'm not going to lie. Checking Alk is 10x easier

 

[User1]

If you're using something like Randy's 2-part for alkalinity (or BRS; soda ash), 18ml isnt much at all (approx .1 dKh/day). You'll only use about .6ppm calcium/day if my math is correct.

I'm using ESV 2 part (only the alk now but I do have the ca bottle).

 

[madweazl]

I'm using ESV 2 part (only the alk now but I do have the ca bottle).

I'm not familiar with the product; how much does 18ml boost the alkalinity in your tank?

 

[User1]

I'm not familiar with the product; how much does 18ml boost the alkalinity in your tank?

I had to go back to my notes. I was using one of the calculators and when I first started my ALK was in the 7.8 range. I added 20 ml per the calc and it raised it to about 8.1 - 8.2. This does was a manual dose. I then let it ride out a week, tested manually, checked the Trident, and saw it go back down. Here I said ok, 20 ml seems to be what I should dose if I want to hold it steady.

Not scientific but seemed to work. I think that is about .30 dkh. It really isn't much I guess in the big picture.

 

[Silver14SS]

Just the ALK. I was going to run through the Ca and Mg this week.

I'm not going to lie. Checking Alk is 10x easier

I would guess that the test results aren't exactly right before I'd assume that the tank isn't using Ca and Mg.

 

[((FORDTECH))]

I know this is an old th read but did you get anywhere with this ? I have 300 gallon system I dose 20ml of all a day and 0 cal or mag for months now and cal stays at 450. I do 10% a week water changes with instant ocean also.

 

[Randy Holmes-Farley]

I know this is an old th read but did you get anywhere with this ? I have 300 gallon system I dose 20ml of all a day and 0 cal or mag for months now and cal stays at 450. I do 10% a week water changes with instant ocean also.

You need math, not an unusual explanation. lol

You won't see the expected calcium drop for a long, long time, and it is likely lost into the water changes.

Assuming you mean 20 ml a day of my DIY recipe #1 (like BRS uses), then that is adding less than 0.1 dKH a day, or 0.7 dKh a week.

The expected calcium decline to match that is only about 5 ppm a week.

No hobby kit can reliably detect a 5 ppm drop in calcium, and water changes are going to make the change even smaller.

 

[((FORDTECH))]

You need math, not an unusual explanation. lol

You won't see the expected calcium drop for a long, long time, and it is likely lost into the water changes.

Assuming you mean 20 ml a day of my DIY recipe #1 (like BRS uses), then that is adding less than 0.1 dKH a day, or 0.7 dKh a week.

The expected calcium decline to match that is only about 5 ppm a week.

No hobby kit can reliably detect a 5 ppm drop in calcium, and water changes are going to make the change even smaller.

Ahhh So that makes sense then it Has to be the daily auto water changes replenishing the calcium and magnesium due to their demand being so low thank you for your input. Too bad my daily water changes can’t replenish alkalinity also then I would not have the dose at all

 

[Gtinnel]

I know this is an old th read but did you get anywhere with this ? I have 300 gallon system I dose 20ml of all a day and 0 cal or mag for months now and cal stays at 450. I do 10% a week water changes with instant ocean also.

I'm glad you brought this old thread back up. I am having the exact same thing. I do about 1.5% AWC per day with reef crystals and I have to dose a small amount of alk component of a 2 part, but I don't dose the calcium part. I know they get used up together and I didn't know why my tank only needed the alkalinity additive.