Can You have algae without phosphate

[Dozer1one]

So as the title says it's pretty straightforward. One of my tanks is located in my three seasons room. I know, I know but there was in empty corner that needed a reef tank so needless to say there is some sun that hits the tank early in the morning.knowing the difficulties that would be associated with this tanks placement I run a 36 Watt UV sterilizer and a huge refugium with chaeto and mangroves. I keep up on tank maintenance and do a 30% water change every two weeks I do not dose anything As I replace trace elements every two weeks I test my water a regular basis every Friday. With the same results always
Nitrates 0
Calcium 450
Kh 7.3 .... Lil low ?
Phosphates 0
Salifert test kits... Not expired
So my question is can I have algae growth in my main tank without having any phosphates most of the algae growth seems to be on the side of the tank that the sun does not hit. As for equipment my display tank is 110 gallon my fuge is a 45 gallon my sump is a 30 gallon I also have in this same system they grow out tank which is a 33 gallon I run a 36 watt Uv sterilizer and files cord in a filter sock. I have a Kent Marine Nautilus two skimmer that is rated for a 500 gallon tank running off of my main exterior pump.and use only 0 tds water ( spectra pure 100 gpd RODI ) I change the filters as soon as it hits 0.1 ppm on tds meter.

[thegrun]

You almost certainly have phosphates, but the algae growth is absorbing them so fast that they do not show up on your test results. Yes, I would bring the alkalinity up over 8.0 dKh, 7.3 is just a shade low to my liking.

[ca1ore]

The reality is that your tank is constantly 'producing' phosphates and nitrates regardless of what the test kits say. The goal is to have those nutrients exported as quickly as possible so they don't have a chance to accumulate.

IME avoiding nuisance algae is a two step process. First, makes sure you keep phosphate and nitrate low by employing aggressive export mechanisms. Second, have an army of herbivores that will eat any algae that has the audacity to try to grow in your display.

For example, water quality in my display is very good with no measurable phosphate or nitrate. I have a lot of snails, hermits and tangs. Not a spec of hair algae in the display ..... yet, it grows with abandon on the screen in my turf scrubber. So, even though the test kits read zero, clearly there are enough 'transitional' nutrients in the water to support algae growth - it just gets eaten in the display but not in the ATS.

[Dozer1one]

Excellent advice, and thank you for the quick responses.
Currently I have a small army of mixed snails and hermits but only one sailfin tang and a rabbit fish as far as grazers go so ill head to the lfs later and try and get another tang or foxface to help get rid of it. Right now there is only 4 small patches of it maybe 2-4" in diameter but I don't want my mixed reef looking like a grazing field lol

[Dozer1one]

What do you guys think the best method for bringing my alk up would be?

[thegrun]

I like to use baked (heated in an oven to 350 degrees for an hour) baking soda mixed at a rate of 2 cups per gallon of RO/DI water. If your pH is 8.2 or higher you can skip the heating part but that mix will lower your pH slightly. Do a search for Randy's two part.

[ca1ore]

I've never kept a rabbit fish, but all of my sailfins have been completely useless when it comes to actually eating algae off the rocks. Currently, my yellow is very good. I also tend to find that herbivores do a good job of grazing on algae when it is short, but not so much once it gets long and stringy. Friend of mine has had good success with his Kole tangs.

Easiest way to raise alk is with 2-part, just go slowly. I'd concur that 7.3 is a tad low. I tend to keep my tanks on the high side, around 12. At least anecdotally, seems to help suppress GHA by encouraging coralline.

[Uncle Salty 05]

One of the facts of life is that algae grows in saltwater.
I have never been snorkeling and not seen algae of some sort.
All we can control are which types we grow (macro preferred) and how much.
The more macro algae you have living in your system the less likely you are to have micro algae, GHA and cyano.

[Dozer1one]

I just read Randy's whole article, it's very interesting and a simple great way save money. Should I dose his whole receipt or just the baked baking soda part since it seems to be only my alk that's outta wack?

[disc1]

If you only need alk then only dose alk.

[Dozer1one]

Ok thanks for all the responses.