help with alk/dkh

[mott768]

Hopefully someone can help with the problem I'm having, I have sps dominated tank, my calcium level holds around 420 - 450 but recently I have had insane growth and my alk/dkh goes from 8.0 down to 6.4 - 7 just about every 2 days I have to add esv part 2 to raise it back to 8.0 I run a single stage calcium reactor. my PH holds steady at 8.2 and mag holds steady at 1350. any ideas why I can't keep the alk steady? I use arm media and drip kalk at night for top off water. everything in the tank is healthy , colorful and growing. Any help would be appreciated
Thanks

[Percula9]

I have to assume your corals are consuming it. Also bio-filtration consumes alkalinity. If pH is good and corals are healthy I wouldn't worry about it to much. Try seachem's Reef builder. Maybe up the bubble counter on your reactor to increase its out put. What is the pH of the effluent?

[mott768]

That's what I'm figuring since the corals are growing faster and healthy. I was told since I use ARM to keep the PH between 6.8 and 7.0 I use a sms122 controller and it's holding the PH between that in the reactor. I was also told if I go lower than 6.8 the ARM media turns to mush. So would/should I lower it to 6.6 ?

[bertoni]

That's actually not all that much alkalinity to be consumed, so I agree that upping the reactor output is a good idea. I don't know anything about tuning reactors, though.

[tmz]

I can't figure why your alkalinity would deplete faster than your calcium since you are dosing from two balanced sources(ie kalk and reactor media).
If you lower your effluent ph you will dose more calcium and bicarbonatre in balanced proportions which will not likely generate the rise in alkalinity you are seeking aty lest not without also raising your calcium.
The esv pt 2 dosing sounds right if you are absolutely sure of your measurements and the accuracy of your test kit/monitor.

[mott768]

Thanks for the replies guys, I'm at a complete loss,

My drip is more like a stream coming from the reactor it's almost steady, I tried lowering the ph in the reactor and it helped minimal with alk, calcium was getting high 490 but dkh would be 7 I just can't seem to hold it at 8 where I want it. Would adding a second stage to the reactor help? I also noticed that ARM has course media out now, is that better than the fine ARM I currently use?

Thanks for the Help

[Percula9]

What test kit are you using to measure alkalinity?

[mott768]

I use Salifert test kits

[tmz]

A stream sounds like a lot. How large is your system? Mine runs a a fast drip but that's for five hundred gallons. Perhaps, you should measure your effluent output(ie how many litres per hour?). For effluent ph value consider measuring the effluent that comes out of the tube rather than in the reactor.

[mott768]

My total water volume is around 180 gallons, I'm using the coralife calcium reactor which say's is good for up to 250 gal (I'm sure it's over rated) for over a year, it was good holding cal and alk steady, it's just recently (past couple of months) I'm have noticed a lot of coral growth and the problem keeping the alk up. I also checked the calibration on the ph controller and that is good.

[Percula9]

Try an API test kit to see if it agrees with the salifert.

[mott768]

I was able to borrow another test kit from a friend and both test kits gave me the same reading. So I know mine is good