Saltcorner
By Bob Goemans
By Bob Goemans
Hi Bob,
First, I must say your biological filtration explanations are the clearest I've ever seen! Thank you for that.
I am writing because it is very difficult (almost impossible) to find aragonite in my local area. I have tried contacting suppliers in the US to find out if there are places in my country where I can purchase this material for my plenum, however, no answer yet. But Halimeda is available in large quantities and can be found in many shops. Is that useable, as I understand it is as soft as aragonite? Could be if I use it I might not need a lot of calcium supplements. Am I correct?
Best regards,
André Brianti
São Paulo - Brazil
Dear Andre,
Thanks, and as for your question, the most important aspect about plenum substrate is its physical size. Keeping grain size near the 2 -4 mm is very important for oxygen diffusion. Aragonite is very good since it is soft, but crushed coral would suffice if it were the only media available.
As for the local halimeda gravel, it may be too course and flat-sided, even though its very soft material and dissolves at the same pH as does aragonite. Unfortunately its shape contributes to the material packing tightly and blocking diffusion. And, it also contains a lot of organic matter. For these reasons it does not generally suffice as substrate material for any type natural aquarium. Yet, if the material could be sized correctly and made more three dimensional in shape, the organic material can be stripped out by soaking it in a solution of hydrogen peroxide. The best of the halimeda species for substrate material is 'incrassata.'
And yes, there is some reduction of calcium supplements when a suitable aragonite product is used, but it would not eliminate their use.
Hope this helps,
Bob
