Clevan, if you're only recently experiencing cyano and other problematic outbreaks then I would
guess that you've got an excess of nutrients. That tells me that a little more vigorous vacuuming might not hurt. However, changing only 10% of the water may be a problem in and of itself, without knowing how good your source water is.
The question at this point is, What do you want to achieve? You want less cyanobacteria and/or bubble algae? Then do some big water changes with water you
know is nitrate-free (test before mixing) and hopefully free of other nutrients (phosphates, for instance).
A partial vacuuming of a 3" sand bed isn't likely to cause great harm as long as you don't have a large anaerobic area that could kill off the tank were it exposed. If it were a system under my care I probably would have been vacuuming about 10% of the sand bed all the way down with every or every other water change (and those w/c's would have been on the order of 25%-30%).
If you add more live rock then you won't have to rely on the sand bed to achieve so much biological filtration (nitrification). The live rock, if good and porous, can probably also help achieve a good amount of denitrification (conversion of resultant nitrate from nitrification to N, or nitrogen gas). Right now you've got a ratio of less than 1lb./gallon of tank capacity, and that ratio could stand to go up (try double, easy).
Again, this is just my opinion based upon my own experience.
budhaboy":rpjvd5vz said:
mr_X":rpjvd5vz said:
what kind of worms should we be looking for then, to tell us if our sand beds are aiding in biological filtration?
hmmmm, how about Planula larvae, Nemotoda(round worms), flatworms(not all are detrimental), Echinodermatal(sea cucs), and Hemichordata to start with?
Thanks for that list, JP. Without actually looking those up to see if they resemble what I saw, I'm going to guess that you may have hit at least a few! There were (believe it or not!) NO bristleworms in this set-up. I was just very surprised to see such a depth of what was basically coral rubble to my eye. Yes, there was live rock, but I wouldn't call it "copious" amounts by any stretch. (This was a "personal" tank seen at a wholesaler's, by the way. It was a pretty healthy set-up, if you ask me, even though you didn't.)
Mr. X, I can understand why you've made some of the assumptions that you have, but experience will tell you that this is problematic. I never said that you "have to have worms" to know if
anything is aiding in biological filtration, so where you derived this conclusion I do not know. What I have spoken specifically of is nitrification (i.e. oxidation of nitrogenous waste compounds, beginning with ammonia). Then with the talk of the utility of a DSB I remembered this one system I saw that surprised me with how it was done and how its inhabitants looked.
