Maria:
When I move I want to install an indoor pond in the herp room.
I would buy a shell at a local store and make it VERY large (like close to 300 gallons). I would get a pond filter for this setup. I would also have to do alot of trial and error and basically approach it the way I approached the WD pool. It took a few months to get it to where I was happy with water quality and clarity.
For this I bought a testing kit...and tested for nitrates and ammonia (I found when these two were off the PH was always off). Being it's fecal matter from such a large lizard you would have to at *least* double filter the water...which means take whatever is says on the filter box and double the power per gallon. You would have to introduce beneficial bacteria to help with fecal break down. It would have to be an external filter with alot of nitrate stuff and ammonia pellets....which you would have to check for clogs regularly.
Water changing became a whole lot easier because of the PYTHON system I bought. It uses any sink to pump water in and take old water out...no electricity at all...all water pressure. When quality is bad I do a partial or complete change with little effort while I'm changing the cages. There are people who claim to have installed a natural filter which never needs a water change...I would have to see the dipstick to believe it though
I feel you just can't get away with water changes. Even the people at the local zoo got fed up and took out the pond from the croc monitor cage...but their were alot of lizards using one pond. It would have to be changed a few time a day with all that feces. If you planned it well you could install a drain to help....JG Worlds has one that hooks up to your tolite.
With one monitor it should be doable---just plan on using something better then a kiddie pool--he will shred it like paper with those claws.
