Unfortunately the 100 GPD Dow Filmtec membrane is the worst possible choice of all membranes on the market. In fact it is not even a reverse osmosis or RO membrane at all but is considered by the ANSI/NSF to be a nano filter or NF not RO. This means it is not rated for drinking water use in the US since it is only 90% rejection rate versus 96-98% rejection rate for the 75 GPD and smaller versions. This is critical since for every 2% you reduce the rejection rate you cut your DI resin life in half, imagine how much longer your DI would last at 98% versus 90% ?
An even better option would be a Spectrapure SpectraSelect specially treated then individually hand tested 90 GPD high rejection rate RO membrane which is guaranteed in writing to be better than 98% rejection rate. Mine is averaging over 99.4% rejection even after 4.5 years of usage so DI lasts a long long time. For $45 for the membrane and $5 for a matched capillary tube flow restrictor you can't go wrong.
I would also swap the 1 micron sediment filter for a 0.5 micron absolute sediment filter and the 5.0 micron 6,000 gallon carbon block for a 0.5 micron 20,000 gallon carbon block so you do a much better job of protecting your expensive RO membrane which is the workhorse of the system and in turn makes your DI last longer andwork better. You have to look at it like a complete system, start to finish and each component has an effect on whatever follows it.
Next, once the DI is exhausted replace it with non color changing resin since color chan indicator of condition and very inaccurate. It can change in streaks, top to bottom, bottom to top, not at all, all at once etc. It should also be in a full size 20 oz vertical refillable DI not horizontal which leads to short circuiting or Wwwchannelling for poor treatment. Remount what you have vertically for now so it fills from the bottom up for better DI life and water quality. Use only a hand held TDS meter such as the HM Digital TDS-3, TDS-4TM or COM-
100 to test with as inlines are not very accurate and not temperature compensated so can be off significantly if your water temperature and air temperature are not exactly the same which they rarely ar
There really is no need to build your own system when you can buy a guaranteed 150 GPD system brand new for $150 or the absolute best system on the planet for $269. If pressures are low you can add a booster pump to any system but I would personally stick with an Aquatec 8800 pump as they are the industry standard unlike all the imports flooding the market.
Anoter system you might look at for quality filters and components is the 75 GPD Premium from Buckeye Field Supply, $169 and it includes a handheld TDS meter, DI bypass valve, capillary tube flow restrictor, low micron filters and even a thermometer. Buckeye will try their best to talk you out of a 100 GPD Dow as they know its intended use per the NSF.
Be very careful with those canister lids you have, I have had trouble with hairline cracks right where the nipple screws in even at normal un-boosted pressures. On my inexpensive drinking water system I ended up going to Spectrapure for new replacements as the lids they use are much heavier duty and have twice the plastic thickness around the threaded areas. Many found today are not ANSI/NSF or uniform plumbing code rated and are imported using inferior plastcis, at work we went through dozens of them before switching to Pentek brand which is probably what I replaced mine at home with if I looked.
I like how you mounted it all to make it truly portable but I think I would have purchased a larger top bracket and mounted it all on there. More like this which is my system:
