Alkalinity Dropping Significantly in 24 hours

[jonboyb]

First of all, I run several smaller cubes between 12 and 50 gallons including 2 JBJ Nanocube 28 HQI's. All of my tanks run identical PWC intervals, dosing schedule (amounts vary obviously), and have similar stock lists. Mostly SPS's and zoas.

One of my JBJ 28's however drops 2 full points Alk (dKh test) from 8 to 6 between daily dosing of 2-part (BIG dose too). Other parameters are ROCK solid. I don't want to dose heavier and chance stressing my many SPS's any worse than the swing already does. All corals seem perfectly happy as do the clam and many inverts in this tank....but I know this swing can't be good for them.

SG 1.026
pH 8.2-8.4 based on photoperiod
CA 425
MG 1300

I tried a local forum with no luck. Even had members come over to test my parameters becuase they couldn't believe Alk could drop like that with pH, CA, and MG staying constant......but it does. Any ideas from you guys?

 

[melosu58]

Two questions. What brand salt mix are you using? How often are you doing PWC`s and what`s the alk reading after a PWC. Man that`s three questions.

 

[jonboyb]

I do weekly PWC's of 5 gallons (20%+/-) with SeaChem Reef Salt (I've also used H2Ocean Pro+ and like it.....just can't afford it...LOL). It'll get the Alk up to 8-9 but by the next day it'll be down a couple points and the cycle continues for the rest of the week. I mix the salt a little hot with an SG=1.026 and my fresh mix usually tests out to an Alk of 11-12.

Alk reads 6-7, dose, alk reads 8-9, next day, alk back to 6-7. This tank has some large colonies of ORA and Atlantis Aquarium SPS's and I fear dosing any more. I use B-Ionic 2-part and MG and double dose Alk just to get it up to 8-9.

 

[MarineFlake]

If it were me, I would consider supplementing with superbuffer dkh or something similar. I saw your comment about not wanting to dose more and ithink your on to something. Since params are good verified by others, I would consider dropping the second part and just dosing alk until it is holding where you need, only adding the alk part when other params call for it.

 

[jonboyb]

I still have to dose CA (and occasionally MG) to maintain those steady so I can't just drop them. There are some really large SPS's (especially for a nano) and a clam in there so CA would disappear quickly if I dropped it probably. I think the 2-part solutions are somewhat ionically balanced and designed to be dosed together (and I don't mean mixed) aren't they?

 

[MarineFlake]

The two parts I have used say you can use more of one (or less) if you just need the benefits of one part. Since you've focused in on the alk being the issue, I would stop dosing the alk part and just use either baking soda or superbuffer. A large colony of sps and a large clam are going to use alk, again why I would dose or at least supplement with a seperate alk only product. Two parts, in my experience tend to do a wonderful job at maintaining levels, but can drive up levels of other params you may not really need raised if you use it to try and raise one param or the other.

 

[thincat]

???Would you use "Baked" baking soda or regular baking soda?

 

[Kurt_Nelson]

Do all the tanks have the same bioload as far as fish? What all does the JBJ in question have in it? Does it have more fish than the other tanks? Or does it just have coral in it?

 

[jonboyb]

It has less fish actually. 1 true perc, a yellow coris wrasse, and an ORA phantom blenny. The corals are larger colonies than my other JBJ's, but my dose is also significantly bigger for this tank. I've been using a little SeaChem buffer in the monrings and then dosing in the evening for the past couple days and ALk seems to be increasing slightly (and dropping less). Doing everything in baby steps for the sake of my corals.

 

[MarineFlake]

???Would you use "Baked" baking soda or regular baking soda?

I used 'baked' baking soda and non baked baking soda. Both are very powerful when it comes to adding bicarbs. Alledgedly 'baked' baking soda will lower PH (due to 'running off' the CO2 via the baking process) while raising alk and non 'baked' will raise both PH and alk. I have never monitored PH, only alk, so I can't comment from experience on if this is true. I can say that you need to watch you salinity as both BS (heh BS) and other products used to buffer typically contain sodium. After a bottle or two you will see your SG raising. Its worth noting if you are administering to a small tank. Either way, dosing the two part is not needed if other params are spot on. IMO just targeting the param in question should suffice, using the parts or other methods for maint once the levels have been achieved. The same goes for kalk, if you read, the kalk mix is really designed to maintain a level, the mfg I used (Kent) suggests using a CA specific solution to raise CA to the desired level then administering kalk for maintaining the levels. From his last post, it sounds like he's get'n 'er done ; )