Bad ro water quality?

[SawyerCashMomma]

Hello :) I am new to Reef Central, so please direct me to the right place if this is not it.
We have a massive nitrate problem in our 75 gallon reef tank (up to 80ppm!!!) We did 30% water changes from the store every day for a week and dropped it to about 20ppm. So, we decided to buy the Aqualife RO Buddie to make things cheaper in the long run. Hooked it up, made 55 gallons RO, tested it with API test kits.

Here are my readings:
Ammonia- .25 ppm
Nitrate- 10 ppm
Phosphate- .25 ppm

I assume RO water is supposed to be all 0's.
My problem is, I didn't purchase the additional DI cartridge. Would that fix my problem?
I read that it get exhausted pretty quick. Can anyone also recommend a BETTER RO/DI unit. That the DI will last longer AND will get me 0 readings since I'm obviously dealing with some nasty tap water!

Please help! Thanks in advance!

[Adamant]

Yes, you should really have the DI which polishes the water to 0 TDS.

First thing to do is to get a TDS meter rather than running API tests on the water - that way we can see how bad your incoming water is / how efficient your RO membrane is and make sure everything is working.

TDS refers to the amount of Total Dissolved Solids in the water which is what we want rid of and why we use RO (and DI) to filter the water.

You can get cheap ones from auction sites for about $10 which will be OK for starting off with.

[CStrickland]

Ro water isn't supposed to be pure h2o, that's why you need the di stage
I just got a refurbished spectrapure unit for $150 incl shipping. The high quality prefilters will keep your di stage lasting longer because it's getting pretty clean water to start with.

As mentioned, a tds meter will tell you when the di stage is used up, since it can measure some of the non-water things in the water so you assume that if those things are present other stuff is as well.

Api ammonia and nitrate tests are kinda notorious for being hard to use or inaccurate, when those run out you might want something a little higher-end

[SawyerCashMomma]

Thanks for the replies! Buying the DI & TDS tester, crossing my fingers.

[stingeragent]

Most likely the di. Do you live in an older house? My house was built in 54 and still rocking the original plumbing. Ive had to replace a few pieces and the filth in there is ridiculous

[heathlindner25]

And those API test kits will always give weird readings

[shifty51008]

I would pick up better test kits also like salifert for ammonia and nitrate and a hanna checker for phosphate, youll be much happier