TDS meter and lighting question

[Parnold]

My TDS reading is at 53 on my top off water. Does this mean I should change my RO filters. The filters are only a couple months old. At what TDS reading do people usually change them.

I bought 400 watt MH lighting when starting this tank, it is only 22" deep, is this too much light, they are 14" off the surface with no cover on the tank.. I dont seem to be having alot of success with corals. I do have to add a ALK buffer to keep it from going below 8 dKH but other than that my water seems really stable.

Thanks for any response

[Funky_Fish14]

How big is the tank? No, I wouldnt say thats too much light. I have 2x 400W over my 75 gallon reef... everything is happy. Its only 20" Deep, and the lights are 12" above the tank - Single ended, sometimes I run with glass lids for evap, and sometimes not.

And the TDS in your topoff water depends... Right out of my R/O Membranes (in the new house we are moving to) i get 42ppm TDS, but im starting with 850ppm TDS... What kind of prefilters do you have? Do you use deionization resin? And what kind of water are you starting with? This will all affect how 'good' 53ppm TDS is on your output water, and the frequency at which you need to replace your membranes.

Cheers,

Chris

[hillegom]

Some ro membranes are only 95% efficient. It depends on what kind of membrane you have and what your incoming water is equals the purity of outgoing water

[globaldesigns]

I would flush your filters, usually you need to do this once a month or every 1000 gallons (something like that). Your instructions should show you how to do this, with mine it is just a matter of reversing the lines on the membrane and letting it run for a bit, then putting things back as they were.

My water is ~200 ppm, but once filtered it is only 2-4 pmm. The great thing is that this is without a dionizer (only Reverse Osmosis). My unit is the Coralife unit.

if you take care of your filters and membrane they can last a long time.