Water change adding to my diatom bloom?

[SaracensRugby]

So I am going through new tank uglies, but I noticed that when I do water changes the diatom bloom seems to increase substantially. Is “new” water a possible source? My BRS 4 stage shows 0 on TDS, and I just changed the media a month or so ago. I do have very low nitrates, barely shows up on my redsea tests kits, and phosphates are at zero. Could “low” nutrients enable these blooms to continue on? I am going to start dosing nitrates to get my nitrates up to 3-5 as a side note.

Thanks!

 

[chipmunkofdoom2]

It's possible it will go away as the tank matures, but it's possible the source water could be the problem too. What is the TDS of your tap water? What "media" did you replace on the RO/DI system? What is your TDS before the membrane and after the membrane (but before the DI stage)?

 

[SaracensRugby]

So I changed all 3 components of the 4 stage RODI filter: the 2 different filters, and the DI resin. Incomgin is 3 on the TDI meter, outgoing is 0. How can I check before the DI stage?

I also stir up the sand bed when I do water changes (siphon out poop, etc), could disturbing the sandbed also cause blooms?