How much drain does a large clam put on alk and ca?

[deputydog95]

I had a 6" clam in my 60 gallon reef tank. Was doing fantastic and had had it for quite some time.

At least until I added a foxface recently, which subsequently picked at it till it stressed and died. I couldn't catch the fish and brought the clam back to the LFS for a hopeful recovery but it didn't pull through.

Anyway, I use dosing pumps for my A&B solutions. I had an alk spike recently, over 12dkh from the usual 10dkh, and now my calcium is suppressed to 375 from a typical 430. LPS and some of the soft corals are quite mad.

I have a fairly stocked tank with a lot of SPS. However, I can't account for this spike. Is it possible the clam was using that much alk and ca and it bumped up when the clam was removed? It was growing fairly rapidly at the time.

 

[MondoBongo]

i haven't been able to precisely quantify my all/cal uptake from my clams, but i know they use quite a bit. from what i understand they are putting down new layers inside the shell, as well as on the growth edge. so there is a considerable bit of shell being constructed that you actually can't see, as it is on the inside.

i'd be interested to see if anyone has ever measured the exact amounts for different types and sizes of Tridacna

 

[moliken]

seems excessive for only 1 clam. i assume that there is also a sump so the gallonage is greater than 60 anyway. i doubt one 6" clam could be responsible. not that i have any other possibilities

 

[deputydog95]

Yeah, I don't know what to make of that. Seems odd that the alk spiked with the clam being out of the tank though. Didn't have over night, probably a couple weeks. My dosing is pretty steady using an aquarium dosing unit versus me pouring it in.

 

[Stevenliu9]

I know larger clams sucks the Ca & Alk dry really fast. When I bought my big clams from this guy his main reason to sell them is because he had six 8"+ clams in this entire system and he cannot keep up with dosing calcium & Alk. I now have 3 8-10" clams in my 180 and they do drain quite a bit of calcium/alk weekly

 

[deputydog95]

Now that I have that rotten fish out and once I get my alk and ca back to normal, I'm going to get another largish clam.

It's taken me almost 2 weeks of slowly lowering the dose to get it back to normal (10dkh and 400ish ca). I'll check it a few more times to make sure it's still not dropping before adding another $200 plus dollar clam back in.

 

[firemountain]

Looking to add my 1st clam and I am interested to know as well. Right now I can hold stable with a small addition of Kalk in my ATO, at like 1/5 strength. I am in the process of setting up my Avast kalk reactor, so maybe that will fit the bill as opposed to dosing.

Has anyone here been able to keep a clam with running reef salt and just Kalk addition in ATO, or am I going to have to buy a doser?

 

[deputydog95]

Once I get my tank stabilized again, I'm going to add another. I'll take measurements at that time and repost. I'm a little fearful about putting another $200 clam in till I know got I've got my parameters nailed down again.

 

[hart24601]

I had a 10" derasa and 6" maxima and when they were growing fast I had to add an additional 150ml brs 2 part a day. I moved them to another system and went from dosing 200ml/day to 50 in my 65.

 

[deputydog95]

Well there you go. I'm glad someone was measuring. Very interesting. That explains the spike in my tank then. And the subsequent state of chemical chaos it's undergone since them. Still don't have it balanced again. I finally got the alk down to 10dkh, but my Ca is lagging at 380. Used to be perfect at 10 and 420. Sigh. I'm sure it will come around. Unfortunately the stress of all that hurt some LPS to the point when they're STN'ing. Although the SPS loved it and went on a big growth spurt despite the Ca dropping.

 

[MondoBongo]

Very cool to hear some numbers! Thank you.

 

[sirrealism]

I wanted to chime in on this to give you or anyone some info on how much clams can use cal and alk. I have a 93 cube with 2 squamys about 13", 1 crocia 6", 2 maxima 1 7" the other 4". The 7" maxima is new. I have had the same dosing set up for about 6 months and it was 1 gallon of alk per week and a gallon of cal would last 3 weeks. This is DIY cal and alk so its very strong. IE 400mg of kent turbo cal for one gal. 594 grams or about 2 1/4 cups of baking soda for alk per gallon.
3 weeks ago I added the 7" maxima and did not think to adjust my doser. I tested my water a few days ago and my cal was 240 and alk was 6. My normal levels are 475 and 9 so that one clam used up that much in less then a month. My point here is that you have to stay on top of your numbers. As the clams grow they need more. the larger they are the more they need. There is no formula for how much. Most reefers say that clams use a lot of calcium but I have found they use more alk then calcium but every tank is different. I will also admit I changed salt "My LFS was out of RSCP so I got RC. I am sure that did not help as most know RSCP is high in alk and cal but I did not think it would make that big of a difference. I am back to using RSCP and for that tank I will not change again. Now I just need to get my numbers back up.

 

[deputydog95]

Interesting. Thanks for posting!

I added 4 new SPS frags a few weeks ago and got lazy with my testing. I normally run 10dkh and around 420 Ca.

Between the new frags and the growth of the existing colonies, my skh was 9 and the Ca was 350.

I had always been told that alk and ca were consumed at a 1 to 1 ratio. When I had the clam I had to add more alk than ca, although now that the clam is gone and the tank is predominantly SPS, I'm adding about 15ml more per day of calcium and it still runs low.

 

[erndog1001]

Well I guess I'll throw in my 2 cents here.I have six clams at the moment. They vary in size The biggest is about 10" Then 7-8 " 3- about 5" and 1 like 4". And I have my eye on at least one more at my LFS. Yeah I love clams!! Lol
My system is 400 gals. I do dose alk. But a once a week water change of 75 gals seems to fulfill all my Ca needs. And I have lots of SPS So I guess the sheer volume of water is sufficient to provide for all the inhabitants.