Need help w alkalinity

[Reefdiver77]

My alkalinity continues to drop. My parameters are:T 80.2 sg 1.025 calcium 440 alk 1.60 ph 8.3 ammonia 0 nitrites 0 nitrates 20. I know the nitrates are high, as they have remained no matter what I do. Cleaned sponges, regular water changes, decreased feeding, blown trash off liverock with powerhead, etc. (Plan to use Kent Nitrate Sponge after I make a bag for it this weekend).My calcium remains wnl, but my alkalinity is dropping. Last week it was 2.06 and now it is down to 1.6. I have not dosed the Kent Marine Tech cb parts a&b for a couple of month since my alkalinity and calcium were wnl. I planned to add baking soda to get my alk up, but am unable to get the reef chemistry calculator to do anything (my computer???) and need precise measurements for this addition. Is there one part of the calcium buffer I could use to only raise the alk and not the calcium? If so, do I just dose it as directed on the bottle? Thanks.

[bshumake]

nitrates are nothing to get worked up over, they just indicate that your bacteria are alive and healthy. If I didn't see nitrates then I would expect to see some ammonia and nitrites... unless its a large system and then that would tell me that its so dilute that its not being picked up. Your calcium is actually at the low end of normal with the scale pretty much a sliding one (400-500: with 440-500/550 being the scale I follow) so its kind of a toss up. Try bringing up your Ca to 480 with the a&b and see where that puts the alk. Also, search for baking soda here and you should get a nice lott of info. Keep in mind that baking soda will also raise your pH.

[Codeman00]

I think I can help on this.

If you haven't been using your Kent Marine Tech at all, of course both your alkalinity and calcium levels should be dropping but they shoud be dropping evenly...but you mentioned that its only your alkalinity that is dropping. I'm not going to go in depth into this, there is a heck of a lot more calcium in your water than alkalinity reserve...so alkalinity is used up quicker. Combine this with you using a salt mix that is notoriously high in calcium (600ppm) is causing you to have consistent normal to high calcium level with dropping alkalinity. In other words, I think your water changes are keeping your calcium up but you arent supplementing any alkalinity and you need to keep them at the appropriate level and consistent what ever you do. Most people that use a salt with normal calcium level (like Instant Ocean) see a normal calcium and alkalinty drop so they can use a balanced 2 part additive to keep the Ca and Alk up. Now you know why I dont use Oceanic anymore...

You can add baking soda as alkalinity instead of one part of your expensive Kent buffer chemicals to achieve the same thing. Are you filling out all the blanks of the reef chemistry calculator? You need to fill out gallons, current alkalinity in the correct units, desired alkalinity and pick the product that you want to use to correct the problem. It should work if you do that...read the directions for your tank additions.

If you have any other questions, let me know. Get that alkalinity up..your clam needs it.

[Codeman00]

Per Randy and the Reef Chemistry forum articles..440 is on the high end for a reef tank but still okay. Anywhere from 380-450 is good with 420 being the typical ocean calcium level. http://www.reefkeeping.com/issues/2004-05/rhf/index.php I would consider 500 to be too high and I dont think Vickie needs to worry about raising it anymore.

Baking soda reall doesn't do anything to the pH....its non reactive with the CO2 in solution. Washing soda on the other hand is what raises the pH because since it actually pulls the CO2 (and thus carbonic acid) out of solution to leave plain water. This reduces the acidity so be careful when adding it to raise alkalinity. Just dont do it too quick and follow the reef chemistry calculator for instructions.

[bshumake]

Its late, I should go to bed. Cody's on the job. My brain hurts.

[Codeman00]

Sorry Barrett...I didnt mean to step on your toes.

[bshumake]

Oh no man. No toe stepping. Its all good in the hood. I'm just misinformed. Good job man. I need to refamiliarize myself with the parameters. The baking soda was a mistake cause I've been making washing soda in the oven and since its pH is like 12 i was thinking baking soda was a little basic to begin with.

[crpeck]

Hi Cody,

Did you really find that your alkalinity stayed low with Oceanic? I've been using Oceanic for almost 2 years and have come to accept that 2 part dosing is just a fact of life. I do get sick of it, though and wonder about changing salts some times.

Did you have to dose with Oceanic and not have to dose with different salt?

Cathy

[Codeman00]

Hey Cathy...I guess let me explain a bit about the Oceanic. When I first started my aquarium, I was told by a friend to use Oceanic salt because the calcium level was higher. I thought that was a good reason; but at the time, I really didn't know anything about the reef chemistry stuff (alkalinity, and how Ca and Alk work together). I tried then to get my Calcium down and it took forever to get it within the proper range. I was doing a lot of message board reading on the best salts and after a lot of conversations with Randy on the reef chemistry forum, I realized that having a salt with a super high Calcium level wasn't really desired because the idea is to keep your tank Ca and Alk balanced. To do this, its best to use a salt that has a Ca level close to what your normal parameters are the levels dont fluctuate at all after a big water change.

Using Oceanic won't keep you from dosing...but it can mess up a 2 part dosing schedule depending on your tank demand vs the amount of water changes you do. I think that's what Vicki is running into...her alkalinity is being depleted but her water changes keep the Calcium levels extra high so she doesnt need to 2 part dose, she only needs to keep up with the alkalinity. I personally find it easier and also have read that its better to have a balanced dosing schedule than an unbalanced...so I changed over to Instant Ocean and now I have a calcium reactor.

To answer your question, I did have to dose somewhat with Oceanic, but my tank was new and it had little demand...I quickly learned the above and switched to Instant Ocean and have been with it for most of the time. I also learned that Oceanic has other different component ion levels than natural saltwater and he feels that Oceanic is not the salt of choice. Many people use it with no problems so it might be a matter of opinion. You might want to do a search on reef central for Oceanic and see what everyone else has to say.