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BGA in a low light aquarium

sanj

Member
Joined
10 Apr 2008
Messages
1,531
Location
Coventry, UK
Hello,

I have a low light aquarium 48x20x28(h) and 120W (4x30w) lighting with reflectors. This aquarium has been in a prolonged period of neglect for about a year after i lost insterest following a major mishap in my other aquarium over a year ago.

Anyway I now have regained the enthusiasm to restart, but in the above aquarium thereis BGA infestation, i am currently blacking out after doing a major water change and clean up. BGA was there before i kind of gave up, but I was not dosing then. My question is should i add KNO3 to this aqurium even though i am not adding CO2 and the lighting is low? Is this likey to eradicate BGA? If i should how often would you do it in this situation?

Have to say i hate the stuff, dont have an issue with other algae.

Now that i have just ordered a python the biggest bain of the hobby (IMO) waterchanging might not be as much of a chore.

Oh and BGA is the second bain of the hobby...or at least i hope it wont be if i can sort it.

The other aquarium 60x20x24 will be a high tech, but this time i will do EI dosing from the start. It has 4x 54w T5s, co2 etc. :)

Thanks
 
Personally, before you even worry about dosing anything you want to give the tank a really good clean and syphon out as much BGA as possible, daily if you can, and really get the tank sparkling clean. Clean the substrate by vacuuming it heavily where possible, clean the filter to up the flow rates and up the water changes.
What filter does your tank have because I've always got rid of BGA by making sure the filtration and flow was very good, without dosing anything.

Once you've got on top of the BGA then start adding CO2 and ferts to get the plants growing well so that the algae doesn't return.
 
Hi Ed,

Thank you for replying.

it has an external fluval filter. I have done one big clean up and will do so again on the weekend. Do you think i should add co2 with the lighting I have(<2WPG)? The current flora is just java fern and crypt species, doing ok. i think there is some dormant Aponegeton sp. and tiger lotus , but they have not grown in the last year.

I will plant it up more again, but not until i have cleaned a bit more... still some detritus around even after through gravel cleaning.


Thanks again.
 
YES!!! The sooner you can add 30ppm CO2 the better in my opinion. Do this before upping your lights and, in my opinion, before you start dosing too heavily.

I've found with BGA that syphoning off every little bit I could every day was the best way to get rid of it rather than just do large weekly changes (do them too; you can't change too much water at this stage).

I'd get some fast growing plants in there as soon as possible too. Something like Hygrophila polysperma will grow well in all light conditions IME!

Don't worry you will get rid of it.
 
Ed,
The only thing I disagree with is the suggestion to not dose. BGA is usually correlated to low NO3. Addition of CO2 will immediately increase the NO3 uptake demand and may even support the BGA so why would you not dose NO3? Of course, this is stated to be a low tech tank so the dynamics might be a bit different. In fact, if this tank does not have BBA then that should mean that the plants are already adapted to low CO2. I would have thought removal, water changes and NO3 dosing would be a quicker sequence.

Cheers,
 
I didn't say don't dose, just sort the CO2 first! ;)

I've had BGA a number of times in tanks and they've always been pretty low turnover breeding tanks where there are too many organics due to heavy feeding and not wanting to disturb the tank too much. When I've cleaned them up and upped the filtration the BGA has gone, even in tanks where I use RO water and no ferts. I'm not convinced low nitrate actually encourages BGA, just that BGA can grow in low NO3 due to its ability to fix Nitrogen. I think the key is often reducing the organics, at least it has been for me. I know adding macros shouldn't hurt either but I prefer to sort things out before adding them and upping the light and upping the growth of all the stuff in the tank.
 
OK, I'm with you Ed but I figure it's better to reconstruct sanj's problem to better analyze. sanj's tank is a low-tech, low-light non-CO2 tank. He states that his other tank will be high tech, not this one.

Based on this data I reckon it should be the goal to eliminate the BGA without changing this aspect of the tank. Therefore, why add CO2 to a non-CO2 tank? :wideyed: If sanj wishes to upgrade his tank to injection that is a separate issue but he clearly states that there are no other algae in his tank. This suggests that poor CO2 may not be a causal factor.

Secondly, it was stated that "...BGA was there before i kind of gave up, but I was not dosing then..."
To me this is an indication that low NO3 due to deficiency is a distinct possibility, however poor filtration and poor maintenance is also a possibility due to neglect. It seems to me therefore that improvement of maintenance, mechanical removal and resumption of dosing would be the key to this scenario. If the plants are already Nitrogen limited then they will continue to leech NH4 into the water column lowering the effectiveness of all other procedures. Weekly non-CO2 EI dosing is called for here it seems. This should help the plants recover quickly and to stop leeching NH4 which may be feeding the BGA.

Cheers,
 
Weekly dosing, that was somthing on my mind...the frequency, thanks for that.

I was going to keep this one low tech for the moment as I do not know if I could handle two high techs right now with all the maintenance. Having said that I have ordered a python, which I hope will take the pain out of lugging buckets back and forth. :) Do you guys use somthing like that? Hope they fit to taps easily.

I mixed up the filter (why did i say fluval?) it is a Rena XP3(350gph), the aquarium is a Rena Aqualife, the high tech is a rio 400.

Ever since i was 10 (now early 30s ehem) i have had boughts of BGA, cant stand the nasty slimy cyanobacteria, but now there does seem a way of keeping it at bay. Dosing, oh and keeping up the water changes. :p

I never used dosing before (dry ferts) but having read the posts on here, it makes sense.
 
sanj,
A couple of things about the non-CO2 tank:

The dosing scheme in the EI dry powder article is fundamentally geared towards high tech tanks. T. Barr estimates that growth rates in a low tech tank are 5-10 times slower than those in a high tech tank so we don't need near as much dosing. Assuming you have a normal fish loading you can dose the following:

A 20USG tank would get weekly - 1/8 teaspoon KNO3 and 1/32 teaspoon KH2PO4

The tank size you quoted is 48x20x28 = 26880 cubic inch = 120USG (more or less assuming your dimensions were in inches)
120g/20g=6 so multiply the reference dosages by 6.

120USG would then get weekly dosing of 3/4 teaspoon KNO3 and 3/16 KH2PO4.
For traces you could probably get away with weekly 1/4 teaspoon CSM+B or 20ml TPN, or any commercial trace dosed per bottle instructions.

If you don't want to mess about with powders you could just use the all-in-one solution of "TPN+" and just dose per bottle instructions. Since you would only be dosing on a weekly basis the cost/benefit ratio is much lower than it would be if you were dosing a high tech.

Additionally, Barr recommends that you avoid water changes in a low tech tank. This is so that the CO2 levels are not disrupted (tap water is high in CO2). So once you get the BGA sorted you may want to consider this strategy. Some of the low tech keepers here may want to chime in with regards to their water changing schedules.

Cheers,
 
You can do either. Personally I measure the dry powders into a plastic beaker with a sealable lid and add some water, screw the lid on, give it a shake untill the powders disolve and then pour it into the tank into the filter flow :)
 
Agree with Steve. I just chuck the powders in like putting sugar in my coffee. The easier something is to do the greater the likelihood that you will continue to do it.

Cheers,
 
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