Can you let us know which test kit you're using please?
As the tank has only been running 5 days it's a bit soon to be testing for nitrate. It should still be pretty much the same as your tap water because there hasn't been enough time for the two bacterial colonies needed to grow yet.
At this point the only thing you need to test is ammonia to make sure you dose to the right level and maintain that level while the tank cycles. Once the ammonia begins to drop daily by a small amount you can test for nitrIte as well, and when nitrIte starts to fall, that is the time to start testing for nitrAtes. That would be 2-3 weeks from when you started adding ammonia.
RO will have zero nitrate so I wouldn't expect to see any in the water after 5 days which means you're most likely testing correctly.
I'm afraid I'm not well up on which kits are good on the marine side these days, but years sgo the ones that tended to be most recommended were Salifert test kits. They were liquid titration tests though. I think you'll find that type is still the best.
When you say you are beginning to see red, green and brown algae what do you mean exactly? Has something formed in your tank? The only thing I can think of is cyanobacteria. Which is often married to new setups (new tank syndrome). It is caused by excess pollutants in the water such as phosphate and exacerbated by intense lighting. You should not have this if all of the water is RO.
Regarding the nitrate testing. It is way too early to have nitrate - it needs to be converted from nitrite via ammonia. What did you use as an initial ammonia source to get the cycle up and running? I always use 1 baby prawn, leave it for a 24 hours, then remove it. That always kicks my cycles off.
Evolutionary Biologist + Fish Enthusiast! Former Aquarist atSEALIFE Member since 2007
i've been following the set up instructions that come with the red sea max, looking various other websites and speaking with 2 guys from 2 separate fish shops.
i've got brown and red algae appearing in the sand and i have purple, green and brown/red algae on the live rock. some was obviously already there.
with regard to starting the cycle, the red sea max comes with a fluid that you add to the water, not to hand so can't remember its name but the guy in my local store said that that is fine to use.........does this do the same thing as your prawn?
with regard to the nitrate testing..........i simply misread and did a nitrate test instead of nitrite.
bought a new test kit today, API 5 in 1 test strips so hopefully these will help me whilst i'm learning the ropes.
hate to be the bearer of bad news but strip testing kits are useless. you need to get a good quality liquid test kit like salifert. the paper ones are just not up to the job chuck em away and get something better
Just completed a water test and i'd just like to see what you guys think of the results and where you think i'm at (i will be taking a sample to my lfs tomorrow so they can test the water for me too).
KH 40 PH 6.5 - 7 Nitrite 0 - 0.5 Nitrate 20 - 40
Wasn't quite sure which colour i thought the test was closest too with the PH, nitrite and nitrate.
At this point, my tank is being over taken by brown/red algae (which again, i supposedly normal for a new tank) but i'm not told whether i should leave it or whether the clean up crew (when i eventually get them) will deal with this???