It's hard for me to say what's a good RO/DI without knowing the chemical composition of the water that's resulting in your TDS readings.
It could be compounds that RO completely gets rid of. It could be compounds only DI gets rid of. It could be a mixture.
The point of any RODI unit is to reduce TDS to 0 so they should all work. I would weigh the factors I mentioned in RODI selection (waste ratio, filters, and GPD).
As for something that can attach to a faucet.. that greatly limits your selection. They tend to be RO only, at least the ones I've seen. Also, not all faucets are compatible. They tend to work on "utility" faucets and not something like a Grohe or Kohler designer faucet.
To widen your options, you should be able to get an add-on T plumbing part in which you can direct the new outlet to a standalone RODI unit. It may require a few parts, maybe even a hacksaw in older situations, but I can't tell you without seeing your plumbing situation.
Though really the easiest thing to do might be to just buy RODI. Most places sell it for $1/gallon. You're not dealing with a large system and you're not changing water that frequently. You'll most likely use it for top off and occasional water changes. Going with a RODI unit versus buying it from somewhere depends on your usage. You can do the math to figure out when you would break even, etc. Buying the RODI water also means you don't need to replace filters, etc, so make sure to factor that in. You can even buy premixed saltwater or natural saltwater.
Originally Posted by CrypticLifeStyle
My 6g planted Bowl on the kitchen counter has a TDS reading of 84. I drain 30% every few days, and just fill back up with the faucet hose untreated.
Now as mentioned earlier my 20g planted had a TDS reading of 197, and tonight 182. I do dose flourish once a week in it, and 50% water changes ones a month.
My faucet a few minutes ago read 92. I also started a 20g reef project a month ago, and want to do for now 25% a week water changes. What would be a good RO/DI given the faucet readings, and RO/DI needed each month, that i can hook up to the faucet as i cant really install inline with the piping as i'm leasing the house lol.
I tried grabbing a water quality report for Humarock, but cant seem to. I'm in a proxy of Scituate, but marshfield supply's Humarock's water.