JBL ProAquaTest PO4 Phosphate Sensitive

JBL ProAquaTest PO4 Phosphate Sensitive measures phosphate at low concentrations in fresh and marine aquariums and in ponds, with around 50 measurements in the kit. The sensitive range is the point of it: in a planted tank or a reef the levels that matter are too low for an ordinary phosphate test to resolve.

Key Features

• Sensitive range: built to read the low concentrations that actually matter in a planted tank or a reef.
• Around 50 measurements: JBL's figure, with vials and reagents included.
• Comparator block: JBL's comparator sets the sample against a blank of the same water, so the water's own tint does not read as a result.
• Fresh, marine and pond: JBL lists all three.
• One of the two algae nutrients: phosphate and nitrate together decide how much fuel an algae problem has.
• When to test: weekly while a tank is new or while you are chasing a problem, and monthly once everything has settled.

What The Number Means

• Phosphate comes mostly from food. Heavy feeding and a lot of fish for the water volume are the usual sources, and some mains supplies add more.
• Low is the target in a planted tank, not zero. Plants need phosphorus, and a tank stripped of it stops growing and hands the advantage to algae anyway.
• In a reef, phosphate is kept very low because it interferes with calcification.
• Test before and after using any phosphate remover. Dosing one blind is how a planted tank ends up deficient.
• Test the tap water too, so you know what each water change brings in.

Getting A Reading You Can Trust

• Read the colour in daylight, against something white, and not through the side of the aquarium.
• Hold the reagent bottle vertical rather than tilted. A drop counted at an angle is not the same size as one counted straight down, and drop tests are counted in drops.
• Take the sample from mid-water, away from the filter outlet, and test it straight away.
• Rinse the vials in tank water before and after, and never with detergent.
• Write the numbers down with the date. One reading tells you where you are; a run of readings tells you which way the tank is going, which is the useful part.

Good To Know

• Reagents have an expiry date and they drift as they age. A test that has been open for years will quietly give you the wrong answer.
• Store the kit closed, cool, out of direct sun and away from children. The reagents are chemicals, not accessories.
• Heat and humidity are hard on reagents. Keep the case indoors rather than in a garage or on a balcony.
• JBL sells these tests both as a complete set and as a reagent refill. If you need the glass vials, syringe and comparator block as well as the reagents, check which one you are ordering.
• A sensitive test is wasted if the vial is not properly clean. Rinse in tank water and never in detergent, since many detergents contain phosphate.