90 gal fresh water tankt to 90 gal salt w. tank?

Can i switch from a fresh water tank to a salt water tank? I know im gonna have to clean it out and buy a lot of stuff but just wanna know if it can be done? I have a cascade 1200 filter im curently using. I was also wondering if i can use a 400w metalhalide light for my tank, if so do i have to enclose the light? just some very beginner ?'s but im try in to learn so please work with me! thanks boaboi86!

 

Welcome to 3Reef!!!

You can most certainly use a fish tank that was used previously as freshwater as long as it is cleaned properly. Regarding the MH question, let us know what the color spectrum the bulb is. When you say enclosed, do you mean, "Enclosed in a canopy" or do you mean the bulb "is enclosed and protected from water splashes".

I know nothing about freshwater so someone with freshwater experience will have to answer your Cascade filter question.

 

thanks and how do u properly clean a fresh water tank? and can i use a warehouse style mh fixture, and i can buy whatever bulb i need!

 

Clean with white vinegar and water. Rinse very well.

As far as bulbs go, you could technically go as low as 5500K but you won't like the look of your tank (it will be yellowish green). You could supplement that with a bunch of actinic VHO's to turn the tank more white but that's not cheap. Most people go with the higher Kelvin bulbs so they don't need as many actinic bulbs and some people go with even higher Kelvin bulbs and don't need actinic VHO's at all.

 

When I converted my freshwater tank (brackish) over I left all the water in it and pulled everything out, driftwood, gravel, etc.. I then let everything settle to the bottom and I did a 20% water drain and sucked out all the crap. I was keeping my water at pretty close to marine parameters anyway because of having adult green puffers in my 55 gal.
Without adding any water I then put my Agra-Alive sand in and about 42lbs of live rock and let the tank run with the green puffers still in the tank. I kept the puffers to cycle my tank and they did quite well I must say. After the tanks parameters were all at zero I got a cleaning crew, 50lbs more live rock and a clown and then gave the puffers to a friend of mine with a brackish tank.
I probably should of cleaned my tank as inwall said but I was new at the saltwater stuff and didn't know any better.
Either my fish were really hardy or I was just lucky as hell.

 

Well with a 90 you best drill it right up front and install some corner overflow boxes 90's are very tall and unless you have a huge Hang on overflow box the pumps will over run it and a sump is a must. a 20 L works very well for the 90 but a 10 gallon will do. Because of their height they need some serious internal circulation. Just my opinion and experiences with many 90's is what I found is most often overlooked with them.

 

Hi boaboi86- here is some good advise- always listen to the Tangster!