8.96

I don't have any SPS, so Im sure my water changes are enough to keep to keep the levels good

Testing would be the easiest way to tell , but it's not just sps that use up Alk and calcium other animals like coralline , fish , urchins , snails lps and even soft corals all use there share ;)

It comes down to how much all these animals use as a whole , salt can often be enough but just the same it may not.

Some salts contain more or better chemicals while others have less.

Coralline alone can often suck up .5 dkh or as much as 2 dkh in some systems.

The best way to manage is to test and keep a log book , you never know if things could be better;)

Times it by 0.056

Lots of things consume carbonate ions, and thus lower alkalinity. Your skimmer exports quite a bit, organic acids produced by the things living in your tank, and all sorts of calcifying plants and animals you didnt buy make it in to every reef tank. It's a good idea to periodically test, even if you aren't dosing.

Yes 1 ppm is the equivalent of 0.056 dkh :)

I only have some monti caps for sps & hammer coral lps in addition to assorted soft coral. I've been somewhat delinquent in my testing routine, but when I do, I generally find alk to be chronically low. My dosing routine is erratic as well, consisting of throwing 7 to 14 teaspoons of either baked baking soda or calcium into my 7 gallon top off container. Sort of gauge it by when the last water change was as to what I dump in. I've had the tank running for a few years now and recall when I first started the alk being very high. I think that was probably my use of treated tap water from Kalamalka lake (high in calcium & alk) and the fact that I had little in the way of coral using those elements up. Since switching to RODI water years ago, alk is chronically low, no matter what I dose in my haphazard way. I use IO salt & when I test a newly mixed batch the alk is good. A few days after water change, tank tests low again & I'll dump some baked Arm & Hammer into the top off container. Once in a while I'll fire some Epsom Salt into the top off water as well.

Long story short, I tend not to chase numbers as much as I used to in the past. I see my tank every day, stuff looks good, calcifying coral like hammer & especially monti cap are growing like the dickens, there's an abundance of coralline all over the rockwork, back glass. I mostly rely on large water changes every 21 days, give or take, to keep the water chemistry levels suitable for the livestock.

We need a chemistry forum on canreef:)

I do test it, it seems to stay in the recommended range, but i have upgraded to a bigger tank so i might need to start dosing.

With respect to larger tanks needing dosing, I'm not sure that's a valid generalization. I haven't done the math & it would largely depend on the livestock one keeps, but the way I look at it, with more water volume, wouldn't it take longer to use up the chemicals than with a smaller tank? With more volume, you have a greater reserve of those important elements, no? Most of our systems are in a constant state of change, with livestock growing, dying, changing... so I reckon testing is a good thing, particularly if you've invested many $$$s in pricey coral. I think that's why I may be getting away with my lackadaisical testing/dosing routine, I enjoy my tank, but if I'm stressing over it due to a monetary investment, that enjoyment tends to fade quickly.