Help...Ammonia in RO/DI 6 stage system??

[chkm]

I purchased a ro/di 6 stage system for my reef tank and before filling it I let it waste about 5 gallons tested it and got no ammonia or phosphate readings so I started filling up my 150g tank and 55g sump with water. I was surprised after only a few days I had a testing of ammonia so i figured wow i started cycling already (never thought too much because i had lr & ls so i figured thats what kicked of the cycle) well anyhow i kept testing for the next several weeks and saw the ammonia spike very high then the nitrite and then the nitrate, however i still had a reading of ammonia and trite when the trate spiked (very minimal reading) but i just figured the test kit i was using was wrong since i've read multiple postings saying these test can be off (meanwhile i was topping off daily with fresh ro/di water). Anyhow, after my trate spiked real high i figured time to do a water change (even though my amm & trite had low readings that werent going down) so i got it all set up in my brute can added the heater, 2 power heads and IO salt and let it go for 24 hours, next day i take my readings and sure enough i have an ammonia reading!! So I went and purchased new di refill figuring it must be time to change it. I received it and changed it out and used it for a 30 gallon water change on the tank last week and it read no ammonia (coming straight out of the unit and then after i mixed it up with the salt) so i thought woohoo i was right and the di needed changed but then yesterday i filled up and mixed another 30 gallons for a change i was going to do tomorrow and it read that it had ammonia again so I tested the water again from the unit and sure enough i got another ammonia reading...what would cause this after only using 30 gallons with the new di resin and how can i fix it? Im concerned because I do daily top offs with this water and have another 30 gallons sitting for a water change to do tomorrow. Also recently Ive had an outbreak of the red slime, is this what is causing it and how do i get rid of it before it takes over my tank? Any help would be greatly appreciated since im stumped...thanks in advance!!

Heres a pic of my baby

 

[ArgonDreams]

Try filling a small container (a glass will do with RO from the unit directly) let it sit a day and test, then test water from the container, something might be in the container rather then the unit. This way you know if it's the unit or the container.

 

[chkm]

Thanks for the reply argon...I actually thought about doing that but then just decided to test the water straight from the unit to see what would happen and sure enough it tested for ammonia...think I will still go ahead and try the glass just to see what I get.

 

[kau_cinta_ku]

if you have cloramines in your tap water that will cause ammonia.

 

[AZDesertRat]

Two things jump out at me.
1. When you say 6 stage, I automatically think E-bay quality RO/DI unit. The reason I mention this is most of them use poor quality filter elements and who knows what DI resin or how old it is.
2. Have you contacted your local water utility and asked if they use chloramines as a residual disinfectant? This is the first thing that needs to be done before even buying an RO or RO/DI unit so you know what you need to buy.

Chloramines are a tough cookie and require a very good solid carbon block like a 0.5 micron Chlorine Guzzler or a granular catalytic carbon cartridge followed by either a 1 micron or less carbon block or a final prefilter to trap the carbon dust. Then you need a very good quality DI resin like a semiconductor or nuclear grade resin and its most efficient in a 24 oz 10" vertical canister and not a horizontal hollow tube.