Measuring phytoplankton in an aquarium

[williah]

Is there a way to measure the density of live phytoplankton in an aquarium system?

Any equipment or test?

Thanks.

 

[billsreef]

The biggest problem in an aquarium is that unless you are adding large quantities, there will be so little as to be difficult to measure if at all. Probably the best bet would be to filter a known volume through a 2 micron filter, wash the filter into a Sedgewick Rafter counting cell and count the cells under a microscope.

 

[CLINTOS]

I think testing would be extremely difficult when it comes to how many cells are in the tank you could just keep track of the phyto that you add daily and slowly increase daily amount every few weeks and as long as your nitrate/phosphate are in check and you have clear water you can keep increasing until at least you get a raise in phosphate/nitrate or a light tint of green water that doesn't get consumed then this will mean you are adding too much and your critter's/coral's are no longer able to keep up at least until they multiply more

But of course it is important that you now how alive and how consistent the density is in your phytoplankton that you are adding

 

[KarlBob]

Phytoplankton wouldn't be the only thing measured, but you could try turbidity as a relatively easy measurement. As long as you have a skimmer and/or mechanical filter in place, it seems to me that the majority of the turbidity in your tank should be from plankton.

 

[Sig45]

Phyoplankton density is measured in culture before dilution. Florida aqua farms sells a measuring stick that approximates density based on opacity of culture. It's pretty accurate.

Adam

 

[tabwyo]

Take ten 1ml samples from all over your system and view each under a compound microscope. Count up all the floaters and add the ten samples together then divide by 10 for a total sample average. Multiply the result by .001 and you'll have a better than roughly accurate density/liter for the total system. For a firm number of what you have total convert your total system volume to liters (gallons x 3.7854). Then multiply your density/liter result with the total system volume (in liters). This will give you your total system density.