Must have test kits?

[Art]

What test kits do you think are "must haves" to be successful with planted aquariums? You can select more than one.

Let us know your thoughts and advice in the comments. Tell us what is your manufacturer of choice while you're at it.

 

[*Ci*]

Art, your poll has got me questioning a few things.
First, though -
I test for kH and gH because my source water has zero of both and I want to make sure my target amounts are consistent. API is fine for kH, but their gH is too hard to read the colour change for me, so I use Nutrifin for gH (nice, clear pink to blue).

Ammonia and nitrite I don’t test regularly but keep on hand for when I suspect a spike . API for both, but I also have a Haana Colorimeter checker, which gives a more precise ammonia reading.

I have an API phosphate kit, but only use it occasionall. I have 5ppm phosphate in my tap and check it a few times a year to see if it changes. I don’t add or remove any phosphate from my tanks, I just live with the 5ppm.

So that leaves me with 2 questions. Does no one test potassium and why not? I would think as one of the macros, you would want to adjust your dosage based on a test … ?
Salifert seems to be the only maker of a reasonably priced potassium drop test kit, but every online seller in Canada is out of stock.

And secondly, I think I don’t understand iron dosing very well. I thought that iron dissipates (disappears?) from the water column rapidly, so how useful is testing? Do you test immediately after dosing to make sure you hit the target? Am I wrong and the goal is to keep a consistent level in the tank just like the macros?
Thanks for all of your help!

 

[JPog]

I test initially for the usual (NH3, N, P, GH, KH) but once I get into a good routine I pretty much never test again unless a major issue develops which usually has nothing to do with dosing.

 

[BryceM]

I think people don’t test potassium because kits aren’t generally available. I’m a firm believer in using high-quality kits or nothing. I have Lamotte GH/Ca/Mg, KH, NO3, and PO4. I use a mix of RO and tap, so the GH and KH get used quite a bit. I usually only test the others when something seems off.

Poor quality kits will have you making incorrect assumptions, which in reality is worse than not testing at all.