StarF skrev:i guess people would like to know about:
1: correct dosis, and how you convert a running system to biopellets, with out lossing anything.
2: correct flow
Sorry it took so long, but I am not getting notifications of E-Mails. I kind of doubt I have done all my setting correctly, as I am guessing at the Danish! Anyway,.....
Vertex recommends a dose rate of 50-200ml per 100l water. This is a very wide range and depends on the bioload of the tank. I would suggest most new users start with a calculation of 100ml to 100l, as this seems to be a good middle if you are converting from another organic carbon driven system. If you are starting new to carbon dosing (from an adsorber type filtration; GFO, nitrate filter), then I would half the calculated amount and increase over a period of 2-3 weeks to the full calculated dosis. This will prevent a strong bacterial bloom, which turns the water milky.
While on the subject of bacterial bloom, I have had it with biopellets and it has never caused a problem, disappearing in 2-3 days. I have a friend that had a similar bloom with vodka and killed many animals. Two main differences in our systems were (other than vodka vs pellets), my system has strong skimming, which injects air into the water providing much O2. His tank was relatively new (8 weeks) and had a high NO3 level. He had a poor O2 level in the water. Thy key to survival with a bacterial bloom is enough disolved oxygen in the water. Most skimmers provide this with out a problem. I any case, a carbon dosed system must have a good skimmer, IMO.
Flow rates are a bit more difficult to describe. The pellets should be in motion without pronounced dead/clogged areas. The flow must be strong enough to keep the pellets in constant motion without packing them to the top of the media filter. In general, any media filter should not be more than 65% full when not running. I order to remain in motion, they need space. I recommend the filter to be half full, that is to say a 2l filter should contain 1l pellets for optimum function. The more you add, the more likely it will pack-up at the top or have dead areas at the bottom.
Now, to control flow, as I use the Vertex Universal Media reactor, I have an inlet valve already built in. This allows some fine tuning of the flow. As pump, I use an Eheim Compact 2000 for a 2l reactor and have it turned down a bit. This gives me two points where I have flow control. Also, Vertex has made available a secondary top and bottom cap set for the inside of the reactor, which is made with a fine net designed for pellets. I am putting together a photo documentation of how to fill this reactor with shots of correct flow and the new net caps. I'll post it in the next week (I have to write the text!)
Jamie