Matt: thx for the in-depth info. I have been trying to understand why my Alk woukld be low with basically no corals in the tank at all, should have started to suspect my salt. I do happen to like Tropic Marin and have always used it in the past but this was before reef tanks were around. I've been out of the hobby for a bunch of years and this will be my first tank with corals. I do have a Geo 618 Ca reactor but assumed I wouldn't be needing it for a while. My plan was to use 2-part once I started adding corals which require it until the demand rose to the point where a Ca reactor made more sense. Unfortunately I have a lot of the Tropic Marin Pro (Drs Foster & Smith have been selling it for $69/200g bucket with free shipping) but that doesn't mean I won't switch to IO. Not sure I'd be able to sell the TMP since it would have to be local and no one I know of in the 2 reef clubs I belong to uses it ... I'd hate to just throw the stuff away ... I've heard you can add baking soda to raise the Alk but would it be better to dose with Part 2 with the remaining salt I have & then move to IO via water changes ...?
What do you think about IO Reef Crystals? The reason I ask is that a friend of mine just shut down his whoesale reef shop & he had 3 pallets of the stuff he was looking to get rid of ... and I can probably get the stuff really cheap ...
If you don't mind the extra cost and hassle, baking soda or two part adjustment and testing every mix bucket can fix your salt. But I'd recommend keeping it simple.
I'd try posting on Craigslist to sell it before undertaking that mess. IO or Reef Crystals would be a fine alternative...RC is a little more expensive and will raise your levels higher than you need them at the early stages, but not too high. As long as you aren't paying more than IO prices, the RC would be a good buy. Both of those salts are balanced for typical tanks, so either one will do you right.
(Salt dowsn't really have a shelf life, so you could hang onto it until you get the Ca reactor deployed - but I have to say that I'm not even sure I'd want a salt balanced like that in that scenario. Just a thought...definitely would not throw the Pro Reef away.)
agreed, and eventually I will be adding corals so I'd like it to be at a good starting point in the first place ...
This is a good practice to keep in general. Make all your dilutions, etc to get the numbers close before water changes and before trusting all your tests. As AJ pointed out, Alk, Ca and Mg all tend to flux when they are out of balance so you can't even really trust your test kits until the numbers are already pretty close. In practice, if you follow the proceedure below you really won't notice much of this flux. Just for the sake of curiosity, test all three params before and in between each of your doses to see how all the numbers change along the way.
Be interesting to hear others' approaches as well, but I always start by adjusting specific gravity, then test Alk, dose Alk, then test Ca, then dose Ca then Mg... You'd never adjust them all at once without retesting between doses. If a dose is particularly large, like your alk dose will be, I've even dosed 50% and retested before the second 50% just to double check that my progress is what I expected. (Again if your numbers weren't far off, this would not apply so much...for example, on daily doses I always drip Ca and Alk without testing in between because the difference is very small.)
-Matt
You may come to find that alkalinity is a little depressed, but you can't tell by how much without a kit so a specific course of action is impossible to recommend.
