Where's my ALK/CA going???

[Oldsalt01]

14g Biocube, 16 months old. Nitrates and phosphates approaching 0. No corals other than 1 small Leather Toadstool (very healthy), 2 small clumps of zoas (which seem to be receding), one 5 polyp clump of Armageddon (which is also slowly receding), Rock was dry base when put in and now has some lovely corraline as well as the requisite GHA/BHA, some green film algae,  and small clumps of bubble algae. For filtration, I'm running a stock carbon insert in chamber 1, floss over GFO over Biocer ceramic balls in chamber 2. No skimmer. Livestock is: 2 Ocellaris, 1 Tailspot Blenny, 2 Peppermint shrimp, 2 Trochus, 4 hermits, a few Dwarf Ceriths,. Two days ago I brought my CA up to 400, my ALK to 8.3. Today the CA is 320, ALK is 7.3. I have consistently had difficulty keeping both CA and ALK at recommended levels, and I'm talking significant drops when tested every other day. I'm manually dosing with B-Ionic CA and ALK supplements. I realize both are variable throughout the day, but these significant drops have me baffled unless the GFO is pulling them out. I have also had abysmal luck keeping zoas although I am unsure why. My lighting is stock CFL's and moonies. At this point Malawi Ciclids are looking VERY attractive. Can anyone offer some advice?

[vegasgundog]

Have you checked magnesium? It holds the two together or keeps them from binding I should say. Coraline algae growth will consume cal and alk as well.

[Figster]

Believe it or not coralline  algae can consume quiet a bit of alk and ca. Your pic shows a lot of coralline growth so I would not be surprised that is where your water hardness is going. That stuff can drop alk in my 10g by nearly 1 dkh all by itself on a good day.

[RayWhisperer]

Ok, lots of things to work on here.

First, how are you dosing? If you add it too fast, or in a low flow area, most will just precipitate out right away.

Second, how much are you dosing? Adding too much will have the same result as above.

Third, mag levels. Although I don't suspect it, as you are actually able to keep cal and alk levels for more than a few hours. Plus, you are using B Ionic, which has plenty of mag in it already.

Fourth, coralline, as others have posted. It's a pretty big consumer of cal, alk and especially mag.

lastly, as you have already posted yourself. GFO is notorious for depleting cal and alk. Carbon does too, to a much lesser extent.

So, my first suggestion (assuming you are dosing correctly) is to scrape off a sifnificant amount of coralline, do a water change, and see what that gets you. If that doesn't drop your consumption/depletion rate, then, I'd yank the GFO and see what that gets you.

[Oldsalt01]

Dosing by hand, VERY slowly over the course of about an hour, in a high flow area. I was suspicious about the Coraline, but the levels just seem to fall off a cliff over the course of a day or so. I have no idea what my mag levels are. As for water changes: religiously, 5 gal per week, from my trusty LFS, and I've checked their levels before a change and they're spot-on recommended levels. It's not my impression that CA/ALK levels have a significant impact on zoa/paly growth, but this tank has never been good at growing either, except for Pink and Gold palys, which started out great but over the course of six months, they too melted away.

[RayWhisperer]

Alk is huge for softies like zoas. When I had my tank at work running, they were my canary in the coal mine for alkalinity. As soon as alk dropped below 7 they would close up. If I was away for an extended period, I would always return to many a melted  zoa. I tried, but teaching a bunch of non reefers anything about reefs was useless. So, vacation always meant loss of coral, too.

[Oldsalt01]

NOT Being a newbie to salt (my ID should be a hint) I'm just trying to get a handle on this tank. This is my first foray into corals tho, so maybe I am. It just seems to me that I shouldn't have to dose every day to keep the ALK/ CA levels up. I do have lots of Coraline so maybe that's where it's going. I would think weekly 5gal water changes should help somewhat, as my total volume is only about 11 gals total if you account for displacement by the rock. That's about 50% a week. Making me a little crazy!

 

[RayWhisperer]

I'm not questioning you, or you're ability. I'm just giving you a few thoughts on what might be happening.

[Oldsalt01]

No offense taken. Several people have suggested I check the magnesium levels, so that will be my next move. I'll also check the Ph level. This tank may be one of those that just doesn't like zoas. My Toady's loving it tho.

 

[anizato]

Start looking into getting a better light. AI Prime HD or a Kessila160 or whatever... 

Second, I recommend to reduce the amount of water you change a week. 50% is too much! not allowing parameters or organisms to establish, its like a revolving door of water on steroids! 11 gallons total water means you should be doing about a gallon dude! you could even do a gallon twice a week. but 5 gallons a week in one flush ..pff that is a lot!

 

test alk/ca/mg everyday for a month. include testing for new water before water changes, as well as before and after water changes. this is advice that i took to heart and it is the only way you can understand what is really happening. log everything (amounts of dosing, methods of dosing, etc) you do everyday (be specific!) in the same place you log your test results. at the end of the month you will understand and be grateful you did!

[Oldsalt01]

Just checked the Ph. Spot on at 8.1. Will check the mag this week when I get the chance (have to take a sample in to my LFS). Checked my ALK/CA last night (7.8/400) and again this a.m. (8.3/400), so it looks as though the CA is fairly stable, but the ALK varies with the time of day, as expected. I'm going to slowly dose another 5ml of B-Ionic CA buffer for calcium and alkalinity today. I have started logging my test results as well as all my parameters  again. Unfortunately a computer program change somehow trashed all my records of this tank from Day 1- January of this year, so I'm sorta starting over. Guess I'll have to get a Mag test kit too. Thanks to everyone who has given my input so far.

[Clown79]

Alk is important to the whole tank and many things use it besides corals.

 

I have never dosed my esv over an hr, literally take 2 seconds to add it and never had an issue with my params with this method. As long as you wait at least 10mins in between dosing alk and then ca in a high flow area.

 

Definitely check mag because I had low mag and it caused issues with my alk/ca balance. I had to dose mag to get everything in check. 

 

The gfo could be aiding in the depletion.

Could be multiple factors.

 

Have you tested 10mins after dosing to determine its increasing the alk to the desired level?

[bob115]

As others have said, try scraping the coraline off the glass. That sharp of a drop in that short amount of time with the coral load you have makes me suspect some type of abiotic precipitation playing a part. Check magnesium as others have said. I see you have sand, doesn't look like a lot so this may not be useful, but like around the sand to see if you find any clumps or aggregates. Could be precipitating there where you don't see it.