dittos from el dorado, bruce, nice post for #3,000...
victor, i think yer question might highlight the biggest difference between bottom diffusers and circulators like the ones bruce, dwight, and shorty use. circulators dont affect the thermocline as radically as bottom up diffusers do.
so here's my weak attempt at a comparitive analysis, posted for the experts to shoot down.....(actually wondering if we can make a list of generalizations):
circulator - disturbs water surface more and thus fights FA growth better than bottom diffuser,
-doesnt mix water column as efficiently and leaves O2 dead spots in deepest areas of pond,
-not as effective at breaking down muck accumulation
-protects thermocline better which is most important in winter (i.e. does not completely destratify pond)
-contributes to greater evaporation rate in summer months
-on average, uses more electricity?
bottom diffuser - provides more oxygen faster to the deepest areas of pond because the mixing of the enitre water column is achieved faster,
-does not disturb water surface as much, so doesnt fight FA as well
-fights muck accumulation better
-destroys thermocline, and completely destratifies pond
-can potentially harm fish by cycling the anoxic muck up through water column and rapidly raising temps
-contributes some to evaporation during summer months, but not as much as circulator
-on average uses less electricity?
