My tank is 2 months old and it's still in the cycling process but lately when i use distilled water for my daily top offs the algae gets noticeably darker.

I've been using distilled water for daily top offs since day one and this is the first time i've seen the algae react so fast to it.

Should I be de-chlorinate the water first?

And i just dropped the Poly-Filter into my filter since it was said to help remove ammonia phosphates and so forth for my still cycling tank which is when the distilled water started making the algae act up.......

Any suggestions?
Thanks

Distilled water is pure, you dont need to worry about that.

would there be any specific reason why the algae decided to act up all of a sudden though?

chlorine wouldn't be present and even if it was it wouldn't promote algae growth. Could be the sudden salinity change?

Does it happen to be from wal-mart? They switched brands and I am having the same problem.
I since switched mine to RO, but been using the purple cap water from wal-mart for two years with no problems.

Test the distilled water with a TDS meter to make sure you are getting what you think you are. I hate purchasing water since you at someone elses mercy. I will only buy water from a staffed Water & Ice type store, not a vending machine or bottled off the shelf. The store will usually be more than happy to test the conductivity or TDS for you since its their core business. Either that or buy a TDS meter and tes tall water you buy yourself.
The best option is a RO/DI unit, they pay for themselves quickly if you make much water at all.

TDS for distilled maybe... I'd honestly first be testing the water for PO4 (phosphates). I used a lot of distilled water back in the day (Arrowhead brand) and it was good stuff! Apparently other reefers I talked to complained that Sparklettes brand distilled water had a significant or at least detectable level of PO4 in it, which directly corralates to algae stimulation and growth. TDS test it if you can, but for sure test it for phosphates which are NOT detected or measured in TDS readings...

Phosphates can be detected with a good TDS meter but they are weakly ionized so the levels may not be accurate.

Ones with a resolution of less than 1ppm, right? I know at least like a TDS-3 won't detect it.

That makes me wonder how well test kits do especially on DI or distilled water since they are very few ions present? I have never tried but I would think they wouldn't do all that well either especially if its a saltwater test kit that would have built in interference for all the other ions present? Got me curious now.

I know one thing, PO4 kits don't tell you jack on an algae infested tank.

I think for a good true result, one would need a Hanna Colormeter for a true low resolution reading of PO4...