3 Phosphate tests compared.

[jarrod0987]

I decided to test out 3 different phosphate tests on my aquarium which I make every effort to keep the Phosphate below 0.1 ppm.

API Phosphate Test Kit showed undetectable levels.

That is to be expected as this test is in the wrong range for those low levels. It would be more suitable for someone wishing to keep elevated levels of phosphate for rapid growth IMO. Probably not accurate or easy enough to read to be precise.

Easy Life Phosphate test kit showed 0.04 ppm.
This kit is kind of neat. It's color card shows a chart for viewing the vial both from the top or from the side. It also has a high range and low range color chart even though the test procedure is Identical. An interesting thing is that the color starts off dark and gets lighter while you are waiting the required 15 minutes.

My Hanna Checker ULR Phosphorus (Model HI-736) gives 30 ppb which converts to 0.09 ppm.

I really like this test because it just gives me a real number, no color chart to struggle with. This model is made for sea water but Hanna advises me there customers use this for freshwater sometimes. Both there other phosphate checkers work with both fresh and sea water. I am sure it is close enough.


Note: Some criticize this target however I have not had any problems with my plants and very few algae issues. I read in the very rare case of phosphate deficiency the plants dies and fall apart very quickly. I don't know if that is true. It never happened to me.

 

[Delapool]

I'm not sure on phosphate deficiency, usually I get potassium (or CO2 I think) issues.

As an owner of the API test, any plans to run it on higher ranges for comparison. Say 1 or 3 ppm (?) maybe (cough, cough). Also wondering which test kit for your target range that you found best?

 

[jarrod0987]

I'm not sure on phosphate deficiency, usually I get potassium (or CO2 I think) issues.

As an owner of the API test, any plans to run it on higher ranges for comparison. Say 1 or 3 ppm (?) maybe (cough, cough). Also wondering which test kit for your target range that you found best?

I would go with easy life for something simple. It is a bit pricey though. If I wanted the best of the best I think I would go with Hanna HI 717 or HI 736 depending on what range I was looking for. They have a model for 0 to 30 ppm as well but I don't know if anyone here maintains it above 2.5 ppm?

 

[Delapool]

Good question.

I've had it up to 4 with planted tanks. I've heard of tanks at 5ppm (from memory Rivercats had done this).

 

[bcarl_10gal]

High phosphates do not cause algae i run my tank anywhere between 5-10ppm. No nutrient causes algae as long as you have enough in the substrate and water column so the plants are not deficient. the .1 accuracies of these tests do not matter.


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[Delapool]

Another question I have is I was wondering what phosphate level the SW people prefer?

 

[jarrod0987]

Another question I have is I was wondering what phosphate level the SW people prefer?

In a fish only system none.
In a Reef I like 0.03 ppm or lower. It has only recently (last few years) become possible for hobbyists to even measure that low.

The Red Sea Reef Care Program Recommends 0.1ppm for accelerated growth mode (corals may be brown but grow out fast) and 0.02 ppm for coloration mode.