30 gallon now a low light...how to keep it algae free?

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equinecpa

Aquarium Advice Regular
Joined
Sep 12, 2004
Messages
84
Location
Gainesville, TX, USA
In the fall I posted about all sorts of problems I was having with a 30 Gallon Hex. I had too much light, not enough plants etc...you get the picture...tons of algae.

I have changed things around. Last week my tank underwent a blackout, and I unveiled it on Thursday...and it was almost algae free...the water was clear. Finally.

But it is beginning to green up again (4 days later).


Lighting: 1x28 watt compact flourescent ( I had 2 and took one bulb out to go definite low light)

I haven't retested the water because I didn't think I was supposed to be dosing anything yet. I didn't do a water change after the blackout. Should I do a major one now?

I don't want all that algae growing back. I do have macro and micro nutrients if I need to dose.

Carolyn
 
Not sure what all type of plants you have in there or if you are using a co2 system or not, but I would suggest doing a pwc along with maybe a shortened lighting photo period. If your light is on say for 14 hours a day, trim it back to 11 or 12. If its on for 12, cut it back to say 10 hours a day. Give them a little dosing of ferts every week to start off with and see how that goes. Eventually over time your plants will suck the nutrients out of the water and slowly kill of the algae. Keep the feeding (fish) to a minimum as well. Any uneaten food is just cause for more algae to grow. My girlfriend had a bad case of algae on her plants and with reduced lighting period, adding hornwort, and dosing ferts over the course of about a month it cleared right up.
HTH
-Stewie
 
I don't have C02 at present as I don't believe it does much good at this low a light level.

I did a 30% water change this AM and dosed micros. I'll see how things progress.

Carolyn
 
What plants are in there?

IME my low light tanks don't really get any ferts at all - the fish and water changes provide whatever is needed - but this is really dependent on what types of plants you have.
 
I have:

Java Moss
Anubias Nana
Vals
Amazon Sword
Watersprite
Rotala
Moneywort

I think that's about it.

I still think the algae is trying to make a comeback. Anything I should do? I dosed very minimal micros the other day (5 ml) along with the 30% waterchange. Lights are on for 12 hours a day. Fish load is pretty light, 2 breeding size angels, 2 clown loaches and 2 ottos.

Should this tank balance out and grow happily? Or is there something I need to do differently. How often should I do water changes on a lowlight tank?

Carolyn
 
Do some testing and give us the results. Specifically nitrate (NO3), phosphates (PO4), and any results you might get on nitrite and ammonia tests. Regardless of the type of tank (low-light/high-light/non-CO2/CO2-injected) you might have there are certain nutrient levels that you need to maintain in order to avoid algae. IME nitrate levels of 10-15 ppm and phosphate levels of .25-1.0 ppm are ideal. With your lighting you shouldn't need to worry about much else, but I'm willing to bet you have less than ideal nitrate levels if you're seeing algae like you report. Let us know :)
 
i'm not sure if this is true, but i've read somewhere that shutting the light off for about 2 hours a day will disrupt the algae tremedously. Unlike the plants algae need constant light for growth. Plants on the other hand can start and stop photosynthesis anytime of the day.
 
Only a 48-72 hour blackout will have any true effect on most algae. Plants (Macrophytes) will have reserves that allow them to weather this type of 'solar' eclipse but algae, being (in most FW cases microphytes) will not have the adenosine reserves to weather this sort of photosynthetic apocalypse. This is why it works.
 
Ok, did some testing...

Ammonia 0
Nitrites 0
Nitrates -12.5 ppm
Phosphate -between 0-.5ppm (doesn't exactly match the .5)

I thought these parameters would be just about ideal! Yet I can see the water slowly getting a little bit cloudy. The plants don't seem to be doing much growing (I know low light tank = slow growth, but I imagine some growth would be normal).

What else can I do?

The fish are happy... my angels have spawned for the 2nd time in 3 weeks!

Carolyn
 
Most fish don't seem to mind cloudy water, go figure. How are the plants doing? Do you see any noticeable algae (other than the green/cloudy water)? If I read you right you're only running about 1 wpg on this tank right now, correct? Your nutrients appear to be right in line so, unless your kits are way off, I think they're OK. Have you cleaned your filters recently? Many times they can harbor all sorts of nasties even if your tank is good. Just throwing out a few possibilities :)
 
You have extremely low light on what I must assume is a tallish tank, so this is going to make it very hard for the plants. I'd consider putting the other bulb back in, because even then you still have a low light tank, and stop dosing any ferts for the time being. Then watch the plants very carefully for response to the improved lighting, and see if their growth will starve the algae.

Is there any direct sunlight hitting this tank?
 
Plants are OK - not really growing much but not dieing either. I did notice my anubias nana had a tatterred yellowish leaf. My rotala has a little bit of growth, same with my watersprite. But it still seems that the algae is the best thing growing. I would have expected my crypts to do something by now, but no new leaves on them ( the only time they grew was when I went away and just left 1/2 watter per gallon on the tank -go figure).

Am I best to try to waterchange the algae out now or do you think it might be better to try to let the tank find a balance?

I have an HOB aquaclear which I try to clean up whenever I do a waterchange. I rinse the sponge in the waterchange water and scrub off any gunk on the filter. I did put some filter floss in it to try to polish the water some. It has gotten gunky but not as bad as in the past.

I think the kits are OK (I have a couple and alternate their use and get the same readings).

Carolyn
 
maybe is time for some CO2 in the tank. The CO2 will boost the growth for the plants and at the same time out compete the algae for nutrients. You should consider more stem plants like hornwort to help absorb excessive nutrients if you're worried. 1 wpg is too low for the rotala to thrive IMO. Those nasty green algae will grow on the plants if the plant itself isn't growing. GL!
 
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