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View Full Version : Best Way to Manage Diatoms After Cycle


Patrick Cox
02/08/2013, 02:38 PM
I am coming out of the cycle of my new tank and I have a lot of diatoms accumulating on the rock and interior surfaces of the tank. When I run my lights, it gets worse. If I leave the lights off, it is not as bad but turning the lights on brings it back very quickly. I know this is a normal part of starting a new tank but my question is - what is the best way to operate the tank to push on through this phase and also how long can I generally expect it to take?

A bit more detail on the tank...

75G
Bare Bottom right now (will add sand later.)
Skimmer running
Almost fully cycled
Not running GAC or GFO yet, but will start in about a week
No livestock or corals in tank - only cured Pukani rock
Ammonia = 0
Nitrite = 0.1
Nitrate = 25
Phosphate = 0.03
Salinity = 1.025
Temp = 77-78

So, here are some specific questions...

1. Should I run my lights, even though it encourages Diatoms growth?
2. Will adding macro to my refugium help?
3. Should I start running GAC/GFO?
4. Should I hold off on transferring livestock until the diatoms are gone?
5. Any other suggestions?

Thanks!

Kyle918
02/08/2013, 03:04 PM
Since there's nothing in the tank that requires light, it's best to turn it off if it encouraging growth.

I would turn out the lights for three says straight and if you want to go extreme then cover the tank with a blanket. It'll die off quicker with zero light for a long e ouch period. Make sure your skimmer is functioning properly and within a few days it should be gone.

Also, what livestock are you talking about? Are they currently being QTd? If so, just let them hang out longer in the QT. Your cycle isn't done yet as you are still seeing nitrites. How long has the cycle been going so far?

Patrick Cox
02/08/2013, 03:50 PM
Since there's nothing in the tank that requires light, it's best to turn it off if it encouraging growth.

I would turn out the lights for three says straight and if you want to go extreme then cover the tank with a blanket. It'll die off quicker with zero light for a long e ouch period. Make sure your skimmer is functioning properly and within a few days it should be gone.

Also, what livestock are you talking about? Are they currently being QTd? If so, just let them hang out longer in the QT. Your cycle isn't done yet as you are still seeing nitrites. How long has the cycle been going so far?

I am upgrading so my livestock is in my old tank (2 clowns, a BTA and some LPS.) No live rock though because it was infested with flat worms so I started fresh with Pukani rock. Rock has been cooking/cycling for a couple of months. The biological is almost there.

Thanks! I will leave my lights off for awhile longer. Seems like though once I turn the lights on, diatoms pop back up.

nynick
02/08/2013, 03:51 PM
1. Leave the lights on. The algae is there because there is plenty of food for it. Turning off the lights will not remove algae problems in a new tank, only delay them.

2. Yes but don't expect miracles. It is a new tank, the only thing that will fix an algae problem in a new tank is to replace the water with bleach.....

3. Not a clue, never used it.

4. Diatoms are ugly but harmless and lots of critters eat it. I would add the cuc as soon as your water parameters are stable for a week or 2.

5. Many substrates contain silica which feed diatoms, might wanna get it into the tank now while it is an algae mess anyway. Will also be much more difficult to add after you get your coc in the tank as you will probably bury and kill some critters....and if you thought you had algae problems now.... :)

It will be a mess for a while, just expect it and accept it.

Kyle918
02/08/2013, 04:55 PM
I do have to tastefully disagree. Why add fuel if you don't have too? Leave the lights off and let it run its course. Leaving the lights on will delay the eradication of it because you are fueling its growth. Yes it is completely normal for tanks to go through algae problems but you don't have to help it with light that serves no purpose of being on other than looks while the tank is cycling. If he had corals if suggest otherwise.

Patrick Cox
02/08/2013, 05:12 PM
Ok, this is the discussion I was hoping for! Let me ask a question. What makes sense to me about leaving the lights on is that I assume the diatom/algae/cyano (when it shows up) are feeding on the high nitrates. Probably phosphates as well but they are not nearly as high as the nitrates. Then I also assume there are only two ways of reducing the nitrates - high volume water change or algae consuming the nitrates and maybe GFO but not sure about that. So if I leave the lights off to discourage algae growth, won't that just allow nitrates to stay at current high levels and then when I finally move my corals over and am required to run my lights, at that point the algae will take off? Assuming I do a 25% water change, my nitrates would still be about 19 (25 NO3 x 75% = 19 NO3)

Thanks!

Kyle918
02/08/2013, 05:27 PM
Your correct, it is a mixture of both plus the fact that this is a new tank and thus going through the "new tank syndrome". It can actually go away without doing anything and aside from being ugly its harmless.

And you really don't want to add anything to the tank until the cycle is complete. If you have zero ammonia and nitrites but have high nitrates then your cycle isn't exactly complete. Anaerobic bacteria hasn't been produced yet to handle the nitrates properly. You can do water changes though to help lower the levels but until that bacteria population builds, nitrates will be a problem. This is what people mean when they say let the tank "mature" before adding corals. It is because of the nitrate issue and lack of nitrate removal that lends the term, "young" tank.

You can try some nitrate remove like cheato in the fug if you have one. That can help compete for the nutrient and usually will outcompete the nuisance algae.

Patrick Cox
02/08/2013, 05:38 PM
Your correct, it is a mixture of both plus the fact that this is a new tank and thus going through the "new tank syndrome". It can actually go away without doing anything and aside from being ugly its harmless.

And you really don't want to add anything to the tank until the cycle is complete. If you have zero ammonia and nitrites but have high nitrates then your cycle isn't exactly complete. Anaerobic bacteria hasn't been produced yet to handle the nitrates properly. You can do water changes though to help lower the levels but until that bacteria population builds, nitrates will be a problem. This is what people mean when they say let the tank "mature" before adding corals. It is because of the nitrate issue and lack of nitrate removal that lends the term, "young" tank.

You can try some nitrate remove like cheato in the fug if you have one. That can help compete for the nutrient and usually will outcompete the nuisance algae.

Thanks, that makes sense. So at what nitrate level am I safe moving my fish and corals over?

bnumair
02/08/2013, 05:43 PM
diatoms will leave as soon as silicate in ur sand depletes out. this is just a stage and will come and go. algae required lights (either too long hours of exposure or bad week bulbs with lower than 7000k spectrum) and nitrates and phos.
running shorter hours of lights and newer bulbs u can keep algae at bay. along with running gfo will rid phos. nitrates wont just go away unless u have a lot of live rock and the is a great amount of bacteria living in them. chaeto algae in fuge will help rid nitrates along with water changes or a bit more expensive solution is dentrators.

nynick
02/08/2013, 06:18 PM
I do have to tastefully disagree. Why add fuel if you don't have too? Leave the lights off and let it run its course. Leaving the lights on will delay the eradication of it because you are fueling its growth. Yes it is completely normal for tanks to go through algae problems but you don't have to help it with light that serves no purpose of being on other than looks while the tank is cycling. If he had corals if suggest otherwise.

Algae is what removes most of the nitrates, phosphates etc from the water. Without lights, algae can not grow and the dirt stays. When you turn the lights back on one day the algae shows up.

Algae is not the problem, it is the solution and it needs light to be that.

Kyle918
02/09/2013, 12:44 AM
Algae is what removes most of the nitrates, phosphates etc from the water. Without lights, algae can not grow and the dirt stays. When you turn the lights back on one day the algae shows up.

Algae is not the problem, it is the solution and it needs light to be that.

I understand what you mean.

Aren't diatoms more dependent on silicates anyway?