Ya you can double that dose if ya want but be careful and work up to it slowly... Not sure what kalk your using but I use brightwells kalk+2 and I use 3tsp to 5 gal of top off water... Seems to work great in my system... On my big reef stuffed with Sps colonies I was using 2tsp per gallon of top off water...
(Not asking/picking on U angrycubano, I swear...this goes for "anyone." We've all gone through some version of this. ) Once you're done with the need for those instructions is the time when you should graduate to DIY type ingredients such as what you are using. Makes sense in another way too. Money. When you're at the beginning and need those instructions the most, you're really not dosing any significant volume of product, so the price isn't really all the great for the name brand product. DIY comes to the rescue when your corals are big and dosing starts to get heavy! Smart!
Dose Rate
I would lower the tsp by 50% (and dilute your ATO bucket with 100% more water) at least - maybe even go back to straight RO water for top-off until the numbers normalize with water changes, then resume at 50% dose-rate. Also consider getting a reactor to dose your kalk.
Reactor
Tunze's 5074 (my preference) or TLF's reactor are both nice, simple solutions. Tunze gets my nod since it's based on airline-sized tubing and thus can be run by an Aqua Lifter if you don't have Tunze's pump (which costs about the same as an Aqua Lifter, FYI...no reason not to use it.). Never a need for ball valves or any worry about flow rate.
Ca and Alkalinity Usage
Additionally, from your results, there may be close to zero Ca usage in your system. Especially after you consider the effect of your water changes. (You should have a pretty rigorous water change schedule prior to needing to dose kalk, IMO. 20-25% per week or more could be done. Reef Crystals will give you the added Alk buffer you're missing in your test numbers.)
Alkalinity has other factors which can trend it down hard enough to need dosing before coral usage becomes a factor and causes Ca dosing to be necessary too. Did you record any data on Ca and alkalinity levels prior to dosing? You should have (or could have, anyway) seen some indication of this "lopsided" usage there too.
Water Changes
If you have not already, I would suggest maximizing the impact you can have with water changes (no more than 10-20%/day and you can do a water change almost every day....I did 10% daily for quite a while.) while easing your way into dosing using a steady rhythm of testing along the way. Two part is a simpler approach to begin dosing with, IMHO. Kalk is easy to use within a two-part dosing scheme, however as you have the experience.
<soapbox>This case is a good example (thank you for posting and not just lurking angrycubano!) of why I actually recommend folks start out with a quality commercial supplement - Brightwell being my main preference - vs "DIY" type infredients. The reason being: proper instructions. Their instructions for use of two-part, Ca, Alk, kalk and the basics are the best I've seen. Specifically, the liquid Calcion and Alkalin8.3 products are the best of the best and what I recommend most people to start with. They actually give you a good basic understanding, product concentration levels, not just a dosing rate. These two products (along with a lot of reading and testing) got me through the first three years of my reef with verifiably excellent, consistent product.</soapbox>
You'll pay more for Brightwell's product on a per-weight basis, but how much are the instructions on the side of the container worth when they would have steered you clear of this experience? And you would have known the concentration of the product you were adding, so you would have known to avoid this outcome.
Just my $0.02. :angel:
-Matt
