I have a terrible problem with diatoms(brown algae.)

Hello have a 75 gallon saltwater aquarium. I have a terrible problem with diatoms(brown algae.) i have gone through allot of trial and error with my tank. i have Fiji live rock, base rock, and rock from Tampa bay saltwater. i've have not had good success with live rock but i have had good success with fish.

What does that mean "you haven't had success with live rock"? What has happened?

Currently, in my tank is: 1 yellow tank, 1 scooter blenni, 7 Mexican snails, 6 emerald crabs, a sea cucumber, 12 clown fish. i conduct a 12 gallon water change with r/o - deionized water every week. so far the brown algae is slowing down. i just purchased algone which is supposed to improve water quality and rid the tank of algae. i use kalkasser and have read your writings. (they are very good.) my question is should i put the algone in my tank or should i be a little more patient? p.s.-the water is decent and i have lowered my lighting in watts and time? any more suggestions?

No I wouldn't bother with any additives such as algebegone or the like. Brown diatoms are common, fortunately they are easy to remove. The brown algae (diatoms) should only be seem on the glass on sand. Its common to have to clean the glass weekly to remove this. Use a strong algae magnet.
Ideally you should be using ro or di water lights for reef use only (they contain the proper spectrum)
good water turn over 7 - 10x per hour volume of tank
good protein skimmer
Are you using ro or di water?
How old is the tank?

I've had my fish tank for roughly 3 years, my first year and a half i went from freshwater non aggressive to freshwater aggressive then saltwater. when i first began the hobby i purchase some Fiji live rock. i didn't do many water changes so i had several crashes of the tank. all the Fiji died. then, i purchased live rock from Tampa bay saltwater. it was coral encrusted. three bad things happened. first i purchased some so-called reef safe blue legged hermit crabs, they opened up all of the little pods and ate the worms that would go in and out.

Humm well that dosnt sound like it would crash the tank

second, living in the northeast it is very cold in the winter months, well i had a power outage in the neighborhood and the water went down to the teens.

That's a problem, I've always emphasized the importance of a backup system (generator) Reef tanks are very expensive and with all the work that goes in... make its more so

lastly, i did conduct water changes frequently, but the deionizer system i bought totally sucked. it didn't deionize anything so this lead to terrible water conditions and a hell of allot of diatoms.

That's important.. you should have a quality twp in place

Lately, things have gone better, i do weekly water changes (12 gallons per week) and i get my water from a huge pet store that specializes in marine aquatics, also, the snails, emerald crabs and horse shoe crabs are slowly eliminating some of the algae but it always seems to grow on what live rock i have in my tank. it is frustrating. i want to scream. i have had a tank maintenance person come to my home and help me with the tank. he says to be patient. it has only been a month but i wish it could be quicker.

That's good advise, you have to be patient. I would guess getting the water and its cost would in the long run be more expensive than your current method.

Overall reef tanks are very expensive and if you try and cut corners where you shouldn't you can get bad results. see my survey for an average cost of a tank. I suppose the main question is where have you gotten your information from? Who's methods did you subscribe to? I cant really give you any answers to why your tank is the way it is. Possibly, it can be fine and this diatom outbreak is temporary (which is very likely) although I don't think you have an overall grasp of reefkeeping. I don't mean that in a derogatory manner but from the sound of your questions I think you need to get some detailed information and apply it. My book governs all the aspects of reefkeeping in an easy to comprehend manner.

I did purchase algone but it has yet to arrive to my home. is it a good product? will it help me? what should i do?

The short answer, keep doing what your doing and the diatom will probably subside. Don't use the additive to get rid of it. And be patient, definitely consider investing in my book