What would running tap water through a DI filter accomplish?

[dagray]

Our tap water is 7.43 nitrate, 7.2Ph, with many minerals such as calcium.

Running this through a solid carbon block has the nitrate down to 4.3, but only due to the aerobic bacteria in the filter housing.

I am thinking of buying a portable DI filter (high volume) that doesn't have the RO so there won't be any waste as RO takes three gallons to make one gallon (more or less).

[AquaticNerd]

I can't speak to actual numbers here, but without the RO membrane I think you'll find that you're going to expend your DI resin extremely fast to the point where it may not make economical sense for the amount of water you would produce.

You might want to consider a multi-stage particulate and carbon system to see what those results are if you don't want to go full RO/DI. At the same time, unless you're trying to do something specific with modifying your water, I think the parameters you posted above are decent for just keeping fish. Unless aiming for breeding (or keeping wilds) for example, I prefer the stable conditions of my water year round over trying to chase some number.

[dagray]

The reason for not wanting RO is the waste. If three gallons go in to make one gallon of usable water the other two go in the sewer, and I pay for those two gallons.

I am looking at whole house mechanical filtration (I currently have an under sink filter (solid carbon block for drinking water) using a KD Filter, solid carbon block, lime scale filter, and sediment filter with two open manifolds for me to add Nitrate resin like Purigen or the API Nitrasorb. I figure this will work well for all of our water needs, and I can get the parts for about 1000.00 and have it installed for the labor costs.

It is common to have nitrate spikes in our city water, and by myself and a few others in town forcing the issue the city did send samples of our water to a certified lab for testing.

[CliffsDiscus]

Look for Culligan whole house filters, you can buy or rent. Your still going to waste water every time you flush.

Cliff