Alkalinity Testing

dolpator · Aug 8, 2016

I need some advice,

I have been using Hanna DKH HI772 Alkalinity tester and I want to know how accurate it really is. I have been following the directions to a tee and even watched a few videos on Youtube just to make sure I wasn't screwing the test up any. Right now it has been testing 8.8 - 9.3 I am fine with those as long as they are right however, I borrowed a salifert test kit and it read 12 (ran the test twice). SO who do I trust? Thanks for all the responses in advance.

Randy Holmes-Farley · Aug 8, 2016

Both methods seem to be reasonably accurate in most folks hands, so there is probably some sort of problem that is not easy to diagnose from a distance.

dolpator · Aug 8, 2016

I guess is what I need is why the huge variance. Both reagents are brand new, I have watched my tank self destruct over the past few months and I can't seem to figure out what the problem is. I have been using hanna for phosphate and alk, and been salifert for magnesium, nitrate, calcium.
Current parameters in tank:
Po4 .02
No3 5ppm
Alk 9.3
Cal 450
Mag 1480
Salinity 1.025
Temp 78
Ph 8.2
I dose ESV supplements

When I see these numbers I am fine with them. But my tank is not though. So I guess I get freaked out that my take isn't fine and see the variants in the numbers I don't know who or what to believe. Been really heart breaking and everyone I have talked to doesn't seem to have any answers. Except sorry.

Randy Holmes-Farley · Aug 8, 2016

Well, unless it is an ultra low nutrient system, neither 12 dKH nor 9 dKH is causing a tank meltdown.

dolpator · Aug 8, 2016

I have heard the term, and never considered my tank ULNS. Unless it is and I don't know it ? It's not zeo or anything

Randy Holmes-Farley · Aug 8, 2016

If you are not organic carbon dosing in some way, or using excessive phosphate binders, it is not likely to be ultra low nutrient.

dolpator · Aug 8, 2016

Rowaphos is all I use?

Randy Holmes-Farley · Aug 9, 2016

How low is phosphate? If too low, it might qualify as ULNS.

dolpator · Aug 9, 2016

It usually test between .03 - .07 with hanna instruments. I have a refugium with miracle mud, chaeto,and live rock and run the rowaphos lightly. It's also a lightly stocked tank. 9 fish in a 150g

The Rook · Aug 9, 2016

Is it possible your lights are toast or your r.o. meter needs to be calibrated?

dolpator · Aug 9, 2016

4 AI hydra 26s about a year old
R.O. meter? All filters and membranes in ro unit are less that 2 months old.

The Rook · Aug 9, 2016

I meant a TDS meter.

dolpator · Aug 9, 2016

Will research calibrating them. Didn't know they needed calubrated. It is attached to my unit

Randy Holmes-Farley · Aug 9, 2016

dolpator said:
It usually test between .03 - .07 with hanna instruments. I have a refugium with miracle mud, chaeto,and live rock and run the rowaphos lightly. It's also a lightly stocked tank. 9 fish in a 150g

That doesn't seem low enough in nutrients for the alk to be a concern.

The Rook · Aug 9, 2016

Oh don't just trust those. I have one and its pretty far off. I use a $15-$20 HM Digital handheld one off eBay. Then buy a bottle of 342ppm solution to calibrate. You turn a tiny set screw till it reads 342ppm. Kind of a p.i.t.a. but it does allow you to confirm that mounted unit.

midtnmike41 · Aug 9, 2016

What should Alk be in a ULNS? My P04 is always right at .02 and my nitrates are usually non detectable. I try to keep my Alk at 8.5 but it usually swings between 8.4-9.3. I am using kalk in ATO and making up the rest with 2 part. Currently I only have lps in the tank. Below is the rest of my numbers as of this morning. I reduced the the 2 part a little this morning, Ca and Alk are running a little high. I also reduced vinegar a little. I like to keep my nitrates barely detectable. Am I on the right track? Other than little fuzz on some of my rock and GHA growing on the plastic corner overflow my tank looks pretty good, but I am always concerned if its "right"

Alk 9.18
Ca 435
Mag 1410
N03 0
P04 .02
Salinity 1.026

The Rook · Aug 9, 2016

Maybe just feeding the corals more will bring them back.

Randy Holmes-Farley · Aug 9, 2016

I'd aim alkalinity in a ULNS tank for 6.5-8 dKH. Any more seems to lead to burnt tips, possibly because the skeleton grows faster than the tissue can keep up.

midtnmike41 · Aug 9, 2016

Right now I only have a few softies and lps. I do want to try SPS in the near future though. I'll have to work on keeping the alk a little lower. Shouldn't be a problem once I get a few alk hungry corals.

SPotter · Aug 9, 2016

Randy Holmes-Farley said:
I'd aim alkalinity in a ULNS tank for 6.5-8 dKH. Any more seems to lead to burnt tips, possibly because the skeleton grows faster than the tissue can keep up.

Randy, understanding where suggested alk levels should be in a low nutrient system is there anything that says where alk should be in a higher nutrient system? I have a friend who runs his alk around 12, no3 40-50 and po4 around .04-.05 and has amazing growth. Is there any kind of correlation that says if you are running higher nutrients you should also run higher alk?