Yellow rubbery algae

[ChrisD]

Hi. My screen's been up and running for about 2-3 weeks now and seemed to be making reasonable progress but suddenly this yellow algae has caught hold. I did see the previous thread that says it's down to reduced fow but this is happening in the middle of the sheet where it has a good, visible layer of fast flow over it. It seemed to start in the centre and work it's way out as a central band. Right near the edges the screen is greener. Basically it seems to be in the higher light intensity area. (I have 2 18W 2700K CFL lamps about 4" apart (centre to centre) per side on an 8" x 10" screen. Distance from screen to lights is about 2" (splash guards in between). PC fan blowing down over the screen.

Does this make sense to anyone who knows what this algae is and it's growth requirements?

Chris

[routestomarket]

I had the same thing and thought it was due to heat.

To get around it I am now using a stepped light cycle which is 3 on 1 off.

I realise that due to experiments conducted on here it may not have that much effect on yield, it really does help with temp and the growing of green algae!

It may even resolve your temperature problem!

[ChrisD]

Interesting - thanks routes. I'll give it a go. I had wanted to keep 18/6 as a reverse lighting cycle as my display lights or on full intensity for a 6 hr period.

As an aside, I upped the fan voltage to 9V and my temp has dropped to 25-26oC but evaporation has gone silly (for my system) at about 3 to 4 litres per day. As I don't have an auto top off it's not doing my stability and favours. So would be nice if the new cycle reduces heat build up so I can back off on the fan.

[SantaMonica]

Yellow always means not enough flow for your amount of light. If you can't increase flow, then use smaller bulbs, or move the bulbs farther away, or leave the bulbs off a few extra hours.

[ChrisD]

Ahh - ok - so it's a flow : light ratio thing! Thanks. Thinking about it it does tie in with when I increased back up to 18 hrs as opposed to reduced hoursr previously (due to heat in teh pre-fan era). Haven't seen the screen for a couple of days due to a business trip so will be interesting to see how things are tonight.

Will probably increase the slot size as I may be restricting the pump a bit (especially once some blocking comes into play by some stray chaeto). Ideally I don't want to move the lamps as I don't have much room so am trying to keep it all compact.

The lower wattage lamps I have are simply shorter so I guess I will just get a smaller high intesity area as a direct replacement so that doesn't seem sensible for me. Maybe I'll try and diffuse the more central area of light in addition to increasing flow if the on/off or reduced photo period doesn't sort it.

Thinking about it, it may be far more sensible for me to go single sided as I can accommodate the area and could then light from a little further away. Hmmm

[ChrisD]

Well, another few weeks on and I have been using the 3hrs on, 1 off pattern and unfortunately little change (other than it seems to have reduced my evap and temperature gain which is good). Some small strands of more brown than green algae in amongst the yellow but it doesn't look like it's going to win the battle against the yellow gunk.

Think I might look at going single sided (also trying to reduce the noise that has come on since widening the slot for extra flow - might have overdone it). Might also look at running it from the overflow from the tank (c. 600l/h after head reductions from a 1200l/h eheim) supplemented with a small eheim I have (another 600l/hr) rather than running a dedicated 1200l/hr. Flow in my sump must be getting close to 45x its volume at the moment and that's before the skimmer goes on at night :shock:

[SantaMonica]

Decreaset the number of hours of light, first.

[ChrisD]

Ok - will reduce photoperiod by 3 hours over the course of the day. So will run 6 lots of 2 1/2 hours on, 1 1/2 off an see how that goes. Will clean this weekend and hope things go green :mrgreen: not yellow :evil:

[ChrisD]

After much thought I have, unfortunately, suspended algae-scrubbing. Almost 3 months in and I was still not getting any degree of growth that constitutes decent nutrient export. I need to redesign things so it's more compact and the flow to light ratio is right to avoid the yellow algae whilst not sounding like a small waterfall in the cupboard (the rest of my tank is totally silent as I run the skimmer only at night).

In the meantime I am going to take the opportunity to remove the sand from the sump (think this might be part of the problem as the depth isn't quite there for a deep sand bed). I'm also going to look at increasing the flow between sump and tanks so I can use the overflow as the new scrubber feed.

I'd like to say thanks to everyone who has given input directly or indirectly and I'll try again soon I hope with a different design.

Chris

[kcress]

Keep us posted.