Algae Scrubber When Using Co2

[TrickySpot]

Hi Guys,
 
I have my pressurized CO2 all up and running, solenoid works well and level stays very constant at all times. The problem is our local water has a high level of phosphates, and the minute I add ferts, I get algae like nothing before. 
 
I've read that you shouldn't over oxygenate your CO2 tank or even have too much surface ripple. Is this true? I want to build a algae scrubber where the output of my cannister filter goes into a angled trough across the top of my tank's lid with numerous gratings in for algae to grow and high lighting, and at the end deposit the water back into the tank in a convenient hole that the lid comes with.  The problem is, this will cause the water to be in contact with air quite a while and I assume get oxygenated.....
 
Some people with CO2 tanks must have sumps, so isn't that the same story...the sump tank must have quite a lot of surface agitation I'd imagine.
 
I really want to try and do this naturally without phosphate pads/bags in my filters...and ideas would be appreciated!
 
Thanks in advance!
 
Readings:
Ammonia : 0
Nitrites : 0
Nitrates : > 80ppm (But have zero algae until I add potash or micro ferts)
Phosphates : High according to council, waiting for test in the post to get actual reading
GH : > 180 ppm
KH : +- 180 PPM
pH : 6.8
 
 
P.S. One of my other tanks is highly oxygenated, and I have a floating algae platform which works miracles, not a spot in the tank. Poor pleco has to eat store food!

 

[Mamashack]

The only problem with water company results is they are only a snapshot of that day. The next day could be entirely different. I only know because I asked mine and they would gladly send me the results, but also stated that the next time the results wouldn't necessarily be the same.

 

[TrickySpot]

The only problem with water company results is they are only a snapshot of that day. The next day could be entirely different. I only know because I asked mine and they would gladly send me the results, but also stated that the next time the results wouldn't necessarily be the same.

 
That makes sense! But, I've had the same issue 3 times now....somewhere are other posts of me moaning that when I add API LeafZone which is just potash and iron, I get terrible algae, so something is consistent.....either my tap water, or something in my setup/regime

 

[Mamashack]

That suggests to me that it is the ferts you are adding rather than the phosphate content of the tap-water.
Perhaps API Leaf Zone hasn't got the right balance of nutrients for your plants and ends up feeding the algae instead.
Have you considered EI? I haven't used it myself, but if you have gone as far as adding pressurised CO2 why not go the whole hog?
I have seen a website that provides all the stuff you'd need and I know others use it too.
Might be worth a look @ Aquarium Plant Food: 
http/www.aquariumplantfood.co.uk/fertilisers.html

 

[DrRob]

Algae scrubbers I've only ever really seen on marine or predator systems, in the hope of reducing the need for water changes by doing nutrient export. The problem with them is that they'll rob the system of nutrients that the plants need. Given a balance, and enough plant biomass overdosing fertilisers doesn't tend to cause algae, as any of the high tech EI run tanks will show. You could do it, but I'd be concerned that if you got it right then you'd end up stripping the nutrients and CO2 from the system to drive the algae growth. As for the gas exchange, yes, it would be an issue, but the designs I suspect that you're looking at use the high air exposure for the very reason that they're not CO2 enriched tanks so they need to expose the water to a lot of air to get the CO2 to grow the algae, you shouldn't need this.....
 
Personally I'd be bothered about the light, or the flow, as culprits for the algae, unless there simply isn't enough biomass of plants to use the available nutrients and CO2, therefore the algae grows. What's the nature of the set up for flow and lighting?

 

[TrickySpot]

Algae scrubbers I've only ever really seen on marine or predator systems, in the hope of reducing the need for water changes by doing nutrient export. The problem with them is that they'll rob the system of nutrients that the plants need. Given a balance, and enough plant biomass overdosing fertilisers doesn't tend to cause algae, as any of the high tech EI run tanks will show. You could do it, but I'd be concerned that if you got it right then you'd end up stripping the nutrients and CO2 from the system to drive the algae growth. As for the gas exchange, yes, it would be an issue, but the designs I suspect that you're looking at use the high air exposure for the very reason that they're not CO2 enriched tanks so they need to expose the water to a lot of air to get the CO2 to grow the algae, you shouldn't need this.....
 
Personally I'd be bothered about the light, or the flow, as culprits for the algae, unless there simply isn't enough biomass of plants to use the available nutrients and CO2, therefore the algae grows. What's the nature of the set up for flow and lighting?

 
Lights are on for 6 hours a day, CO2 comes on 1 hour before lights, switches off 30 min before they do. There definately aren't enough plants in the tank, but I'm cash poor, rooted plants are so expensive.....and I've got 450L to fill.....
 
What confuses me is that my nitrates at the moment are sky high, as I'd expect.....but why only when I add K2O does the algae bloom? I have about 20 bunches of elodea densea on the way to control the nitrates, perhaps after they are in, I'll try the K2O again and see what happens.
 
The whole EI process is new to me, so going to google it thoroughly now

 
Also, I think what scared me initially was my plants going yellow (iron?) so I added leafzone which is both K2O and iron....postman just arrived with phosphate test, going to test tap water and tank...

 

[DrRob]

How powerful are the lights and how deep is the tank?
 
Also, are you getting good CO2 levels on drop checker or pH and is the flow around the whole tank good?
 
I suspect that the algae is being limited by a lack of nutrients, hence exploding when they're available, but you need to out compete them with plants, which does require some biomass.
 
Overall, I suspect that you may do well to lower the lighting intensity for at least a while to get the plants established and winning against the algae, as it sounds like things are moving very quickly in this tank, which implies a lot of energy input.

 

[TrickySpot]

DrRob,
 
I wish somebody could give me a straight answer on the lighting! If using the old method of WPG, then I have 4x54 watt / 118 gallon = 1.83 WPG, which is low lighting I think....
 
I've switched to the lumen method, which makes better sense, so each bulb is 3800 lumen, which I can double because of the reflectors, so in total 30500 Lumen. The tank is 61 cm (24 inches deep), and according to the scale on another site that puts my lighting way above 'high lighting'.
 
Hence my confusion! I've just received and done the phosphate test on the tank and it was easily 5 ppm +, so I must just check the tap water now to compare....
 
CO2 goes into a powerhead and gets blasted everywhere, I have my drop test on the opposite side of the tank just to make sure it is reaching all over. Apart from the powerhead, there is the internal filter and my cannister filter outputs pushing water around, so I can't believe that flow is poor....though I have ensured surface 'ripple' is minimal.
 
The extra elodea densea have also arrived so they are going in in a few hours.   I've also got fluvals micro nutrient bottle, so now I can add iron, without the K2O.....keep existing plants happy until I can increase the biomass without the algae....I'll keep you posted!
 
Thanks for the help!

 

[DrRob]

OK, lighting.
 
Watts per gallon rules were written back in the day when tanks were all pretty much uniform depths and the tubes were all T12's, which are fine but don't put out as much light per Watt as the modern tubes do, plus there are issues with tube diameter and lighting direction. Essentially, it's a old rule that we can pretty much ignore apart from the fact that is gives us the idea there there are high light and low light options.
 
Lumens are sadly pretty useless for plant calculations. They measure the amount of light visible to a human, so if we see a frequency well it'll bump up the lumen numbers more per amount of light than an area where we don't, so a powerful light outside our best ranges could make algae grow well but seem dim to us. The best example of this I can give are LED hydroponic grow lights, mixes of red and blue LED's that aren't really all that bright to us but make plants explode with growth. Their lumen rating would come up fairly low.
 
If you really want numbers then you need the PAR or PUR rating of a light, which depends on depth of water and distance. Several plant growing hobbyists are getting into getting meters for this now that the prices aren't in the professional meter territory, but it's still regarded as a planting top end luxury item by most and you really don't need it.
 
I'm going to make a guess now, which is that your tank is a 48x24x24 and you're running 4 T5 tubes by the sounds of it. That, in my book, is high light and you need a good dose of CO2 and ferts to keep that stable. I'd turn off at least one, possibly two of those lights, or raise the lighting rig by a foot and see what happens. That's by far the best meter you have available, what's happening in the tank. Your symptoms are of too much light energy, which only works if you blast the tank with lots of CO2 and fertilisers and when it does work you end up pruning every day.