Weird test results

[jmt1030]

So I have a 180g tank with about a 50g sump.

I've been testing for the last couple of weeks and seem to be getting some weird results. As of today, calcium is at 420 and alk is at 8.5. Those numbers seem fine to me, but the weird part is that I've been super lazy with water changes and I don't dose anything. Shouldn't those numbers be lower? I have a decently stocked tank (in my opinion, at least).

Do you guys think this is just user error on my part on the test kits or can the numbers be correct? I'm using the Salifert kits, by the way.

Here's some pictures of the tank as of today:

 

[Randy Holmes-Farley Verified Community Expert]

Are you using tap water? It can contain alk and/or calcium.

 

[jmt1030]

No, using RO/DI water for top off.

 

[jmt1030]

Anyone else? Could my top off water have calcium/alk in it which is keeping the levels elevated?

 

[MnFish1]

Well - maybe the results were higher and are trending lower? I mean maybe the alk started at 10 and is now 8.5 and Ca 520 now lower etc.. To my eye it seems like you have a large tank volume and not that many large hard corals - and if they aren't growing 'fast' you might not be using a lot of Ca/Alk. Every tank is different. You have an awesome wrasse btw

 

[jmt1030]

Well - maybe the results were higher and are trending lower? I mean maybe the alk started at 10 and is now 8.5 and Ca 520 now lower etc.. To my eye it seems like you have a large tank volume and not that many large hard corals - and if they aren't growing 'fast' you might not be using a lot of Ca/Alk. Every tank is different. You have an awesome wrasse btw

Thanks! So what you're saying is that I need more corals?