Please Help!! Hanna Checker 736 inaccuracy

[pgooden]

I am really struggling. I am getting a pretty serious rusty brown algae/diatom (not exactly sure which) bloom on my sand bed and base of rock. Tank running for about a year. Gets really dark by end of day and pulls back with lights out. I own the Hanna ULR checker 736 and I am getting a very different reading every time I use it.

I bought a new bucket of salt because I thought the salt might be the problem but last night I tested freshly mixed 5 gal and I got the following readings (ppb) 50, 10, 32 which translates to .153, .031 and .098 ppm phosphate.

I cleaned the curvettes with white vinegar and pulled some 0 TDS water directly from my RO/DI unit (6 stage) into the curvette to 10 ML and did a test of that and got a reading of 16 ppb or .049 ppm???? How is that even possible?

At this point, I don't think I can trust the Hanna Checker, any thoughts, one on how I can get an accurate, or at least consistent reading for my phosphates and 2, the best/easiest approach for removing them?

Tank is Red Sea Reefer 250 (65 gal total system volume) had since last year
50 lbs cycled marco rock
I am skimming with a RO 110-S
running a single Radion XR15 12 hour light cycle

I want to do a water change but the hanna reader has me nervous to add the mixed water based on those phosphate readings.

Please help!

Thanks,
Shane

 

[Brett H whitt]

I use a Hana ULR and have been very happy with it. I have on occasion had some bad regent packs that had to be trashed. But sooner or later, everything can break. I would invest in an alternate test kit just to make sure something is not wrong with your water supply. I have never seen reading that high

 

[jsker]

I went through that at about 8 months. I might be how you have you light set. If you are not sure go out and get a different test kit and test, or take a sample of water to you LFS and have them test for you.

 

[Randy Holmes-Farley Verified Community Expert]

Unless you used tap water, I doubt there is much phosphate in it, but even if your average number is correct, it is not any big concern (IMO). You add vastly more every day with foods. Manyeople don't realize this and need to keep it in perspective.

I discuss it here:

Phosphate And Math: Yes You Need To Understand Both
http://www.advancedaquarist.com/2012/3/chemistry

from it:

Comparison of Food Sources of Phosphate to Other Sources
What about other sources of phosphate, like the "crappy" RO/DI water containing 0.05 ppm phosphate? A similar analysis will show it equally unimportant relative to foods.

Let's assume that the aquarist in question adds 1% of the total tank volume each day with RO/DI to replace evaporation. Simple math shows that the 0.05 ppm in the RO/DI becomes 0.0005 ppm added each day to the phosphate concentration in the aquarium. That dilution step is critical, taking a scary number like 0.05 ppm down to an almost meaningless 0.0005 ppm daily addition. Since that 0.0005 ppm is 40-600 times lower than the amount added each day in foods (Table 4), it does not seem worthy of the angst many aquarists put on such measurements. That said, tap water could have as much as 5 ppm phosphate, and that value could then become a dominating source of phosphate and would be quite problematic. Purifying tap water is important for this and many other reasons.

 

[pgooden]

Thanks for the replies. I assume when you say tap water, you mean straight tap water without processing through RODI. That was why I was surprised at the reading. I got a 0 reading 3 days ago with the same test kit. Any recommendation on a backup test kit brand?

I am just super paranoid as I have been battling this bloom for a couple of months and don't want to introduce more.

I recently added Red Sea Reef Spec GAC and some GFO in a bag to try and bring it down. Is it worth investing in a reactor and can I mix them in 1 reactor?

I do 5 -10 gal water changes every week but missed a couple of weeks with travel. I feed 1 cube of mysis that I rinse before feeding.

Stock:
1 xmas tree wrasse
1 blue chromis
1 high bar gobey
1 cleaner shrimp
1 pistol shrimp
2 plate corals
1 hammer coral

Any other suggestions?

Here is a picture of what I'm dealing with. Not really slimy but like carpet.

Thanks all!
Shane

 

[pgooden]

One last thing, when I took my measures on Sunday:

Cal 360 (low)
Alk 7 (low)
Nitrates 25(high)
Mag 1285
PH 8.21
Phosphate .03 but don't trust it

I had been relying on water changes to keep things balanced. Doesn't seem to be working anymore.

 

[cmcoker]

Do you clean your sand? Sounds possible a dirty sandbed is the problem as that is where it is all growing...

 

[pgooden]

I syphon it every time I do a water change but it does bring up some cloudy water every time.

 

[Brett H whitt]

Media reactors are not very expensive, probably would not hurt to pick one up. Make sure your GFO is tumbling gently and not getting banged around to much or it will break apart on you. I use Two little fishes Phose-ban because it keeps my Phosphate levels a lot more consistent. For emergency phosphate spikes I keep some BRS GFO around. This stuff will remove phosphate very fast.

For nitrate control I use Chaeto Algae in my sump under a grow light. I never have measurable Nitrates. Water changes will get old very quick if you are using them to control nitrates. I ordered 1 lbs online a year ago for about 12 dollars at most.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks for the replies. I assume when you say tap water, you mean straight tap water without processing through RODI. That was why I was surprised at the reading. I got a 0 reading 3 days ago with the same test kit. Any recommendation on a backup test kit brand?

Yes, I mean straight tap. I wouldn't usually bother measuring the phosphate in new salt water made with RO/DI. There's rarely any uncertainty that the main source for phosphate in the tank is foods.

 

[pgooden]

Ok, I went ahead and changed the water - 5 gal and siphoned bottom. I will do another 5 gal in a couple of days and check the GFO bag to see if it exhausted. I cranked up my 2 pumps (mp40 and mp10) and stirred the sand up so it would go through the overflow.

I will let everyone know how it goes. Thanks for the advice.

On a side note, I was running my Radion 15 with 25% red and green and the strongest area of growth was under the light. My LFS suggested I reduce that to no more than 5%. I made that adjustment and will see if it helps.

 

[Sabellafella]

I am really struggling. I am getting a pretty serious rusty brown algae/diatom (not exactly sure which) bloom on my sand bed and base of rock. Tank running for about a year. Gets really dark by end of day and pulls back with lights out. I own the Hanna ULR checker 736 and I am getting a very different reading every time I use it.

I bought a new bucket of salt because I thought the salt might be the problem but last night I tested freshly mixed 5 gal and I got the following readings (ppb) 50, 10, 32 which translates to .153, .031 and .098 ppm phosphate.

I cleaned the curvettes with white vinegar and pulled some 0 TDS water directly from my RO/DI unit (6 stage) into the curvette to 10 ML and did a test of that and got a reading of 16 ppb or .049 ppm???? How is that even possible?

At this point, I don't think I can trust the Hanna Checker, any thoughts, one on how I can get an accurate, or at least consistent reading for my phosphates and 2, the best/easiest approach for removing them?

Tank is Red Sea Reefer 250 (65 gal total system volume) had since last year
50 lbs cycled marco rock
I am skimming with a RO 110-S
running a single Radion XR15 12 hour light cycle

I want to do a water change but the hanna reader has me nervous to add the mixed water based on those phosphate readings.

Please help!

Thanks,
Shane

Yes buy any of the box checkers or elos professional