why algae grows

[guri]

im using Salifert test kit
NH3/NH4 0
NO3 0
PHOSPHATE 0
CALCIUM 410
MAGNEZIUM 1300
KH 9-10
LIGHT MH two 175w FROM 12PM TO 6PM (cut down two weeks ago)
Actinic (Blue) Bulbs?: from 10am to10 pm
90 g
two skimmers red line for 350g and octopus for 150g
my water amount with sump should be 140g
question is why hairy algae and red slime still grows its manageable not very much but still i have to remove some once a week.?????
any suggestions?
tanks a lot guys

 

[NYreefNoob]

excessive nutrients, bulbs getting old and reaching different color spectrum. PHOSPHATE 0- unless using a meter the test kits are never correct, what kevlar of mh are you using, also cut down your antic period. is the tank near a window ?

 

[Paul B]

Algae grows on all healthy reefs. It is not a disease so it can't be cured. In the sea there are hoards of tangs, urchins and slugs that eat algae. Those animals are there because algae grows on everything, those animals would not be there if there was no algae. That does not work well in a tank because, unfortunaltely there is somewhat less water in our tanks than in the sea and in the sea as I mentioned there are all those herbafores and most of the water is too deep to grow algae. Also those animals in our tanks also poop in there.
The best way to eliminate algae in the display but still keep the benefit of having algae is to install some type of refugium that has better growing conditions for algae then your tank does.
Just my opinion of course.

 

[Arati]

what kevlar of mh are you using

haha bullet proof bulbs?