Yes thats the conversion kit I got, total waste of money.
All you need are the service kits and some liverock. (oh and salt as the service kit only has enough for 15litres)
Yes under the centre tube is a filter that needs to be changed every 4 weeks or so. From what I understand it contains a mix of chemicals (Carbon, ph buffer etc although I dont think anyone knows the full chemical mix) so this needs to be changed along side with the water as otherwise your water will not remain stable.
Sorry, am I missing something here or is the recommendation in the instructions that you use tap water and add the salt they give you to that? Is there some sort of magic filter in the cartridges then that removes the need to use remineralised RO water for marines? Bearing in mind I don't know much about marines I thought you couldn't use tapwater? Or have I got the wrong end of the stick about the instructions? And what happened to things like protein skimmers which I thought were de rigeur for marines?
M-UK I would buy a Salinity refractometer, if hydrometer aren't accurate. This is me just throwing ideas around. I'm not definitely saying I'm going marine. I've only just bought a freshwater API test kit.
Suey2 I've been looking up on this and you can buy Stress coat for marine, if that's what your asking about the tap water.
As for the protein skimmer, I have no idea why they are not needed in the biOrb, I've just been reading up on what they are. They sound like just a filter for organic waste. I could/will be wrong though.
Nagini Ah okay, well it's quite an easy process with a Biorb if you do.
Suey2 Yse the biorbs suggest in their literature you use tap water and stress coat and stress zyme to treat the water + salt sachet 24 hours before adding to the tank. I have used both RO and the tap/sachet method and the only noticible difference is a higher phosphte level in the tap water mix. (well with the tests I do, sure there are other parameters I dont test for that are differnet)
Don't consider using a biOrb for Marine's, it isn't at all suitable. You can't sucessfully convert a biOrb to marine with live rock. There's no surface area and no room for a skimmer, reactors, or proper lighting. You absolutely 100% definitely can't keep live rock or corals in a biOrb. You can maybe keep a very small species (singular) or invert but you will need external filtration which causes more problems. Trust me - don't do it, it's more trouble than it's worth! Oh, and using tap water for salt water is also not a good idea. You need to use 0ppm RO (reverse osmosis) water and a proper reef salt (priced at ?50 - 100 for a 20KG bucket).
Like Ive said before Im not deciding straight away what I am doing. I have an expensive, yet rubbish tank, but I want to put some use to it where I don't harm the fish. This is me researching all my options before I do anything.
Sorry if it seemed like I was determined to go into marine-BiOrb-tank-ness.