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Re: persistent algae problem

> None wanted to comment on my idea that high K is the real problem?
> Roxanne Bittman

I'll bite since I miss it the first time.

I have not found it to be a problem at high levels of light and K+ levels.
Consider some of the lower fish loads I've had, and by lack of fish/critter
waste a greater need / dependence on KNO3, I've had higher than normal
targeted K+ levels. If your KNO3 dosage is high, estimate the K from just
that and pass on the K2SO4 etc.

It could be an unknown
> I still have an algae problem in my 40 gal tank.  It's mainly on the 2
> large pieces of wood and it is primarily red (the "black brush" type).
> There is a small amount of green on leaf tips (hair-like); no glass
> algae and no Cladophora on gravel (yet).

SAE's living in there? They will prune these algae.
You could have mine if you lived closer and the shrimp:)
> Parameters:
> 40 gal
> high light (2x96watt power compacts), high CO2 via pressurized gas and
> internal reactor
> KH = 4, GH=6
> pH = 6.5
> NO3 = unknown, 'cause I stopped looking.  It was between 1-10ppm 2
> weeks ago
> PO4 = 0.5ppm
> iron = 0.1ppm
> K = higher than my Aquarium Landscapes test will discern , >2ppm

How much TMG Flourish etc are you adding and KNO3 and or fish load etc?
> My goal is no visible algae and the tank has been set up since Nov 2001
> and still no success.  I have tried the method of feeding the plants so
> they grow so well they outcompete the algae and that resulted in two
> things: GW (mild) and hair algae (heavy).  Not good.  I cut back on
> fertilizing everything but traces and the greens receded.  The black
> brush algae infesting the wood is the current winner and it's really
> ugly in my opinion.  I've never had this, in over 10 years of planted
> aquarium keeping.

Well, algae come and go:) It can be scrubbed off or take the wood out and
coat with peroxide good and let stand for few then return it to the tank.
I actively go after BBA and remove it.
> My current suspicion is that this is the result of persistent high K.
> I know, you can all start throwing rotten fruit anytime...but, that's my
> current theory.  K was well over 20ppm.  To see if the high K was the
> problem (by any chance) I decided to test for it and bring it down.
> This process has been taking many water changes.  I have made 50% water
> changes once/week for 3 weeks and the K still is over 2ppm (the maximum
> amount detectable by the test I have).  I also started adding barley
> straw extract, so I changed two things (at least) so this is not
> science, too bad.

Well you can and should (at least IMO) attack algae from multiple angles.
But some things are proven, some look like snake oil.
Nothing like scrubbing, water changes, good maintenance, pruning off any
algae, adding good amounts of nutrients back into the tank. A decent filter
helps also. A canister (Hot Mag, Eheim, Fluval etc) all work well or a
wet/dry etc.
I have 20 gallon tanks with 110 watts sitting on them algae free for many
years. The better the filter, the less chance of GW.

> The main change has been that the black brush algae turned light green.
> Yes, it's not black anymore.  However, it seems fine in other respects
> and still appears to spread.  Unfortunately, I have noticed no algae
> death yet.

It'll change color to adapt to lighting and nutrients.
> So, how are the higher plants doing you ask?  Absolutely fine.  I
> change 50% water as described, and only add back traces (TMG) at the
> recommended amount (not more, as I used to).  I add no KNO3, and no
> K2SO4.  When PO4 hits zero, I add a tiny spoonful (spoon from a test
> kit). No plants look stressed and they still need trimming weekly.

Well you likely have enough NO3 from fish?
> So, what do you all think?  Will reducing the K concentration help; has
> anyone else tried this route?

I have only positives and no negatives for K+ additions. I have been using
it for many years and don't find the K+ to be a cause of algae at high or
low lighting, CO2 or non CO2 etc.

> Anyone else had success/failure using
> barley straw extract?

No. Did not help or do a thing in the tanks I saw it used on. I tried it on
GW, did not do anything. Some folks claim otherwise. It's failed every test
I've put it up against thus far so I have difficulty accepting much of what
is said about it for use in planted tanks.

>  What does it mean if the algae changes color?

See above.

> Is
> 2ppm K "way too low" in your collective opinions?

I think so. The plant growth rates I get seem pretty fast in most cases.
I also have no algae with high K+ values. If it's a factor, it's very small
or covered completely up by some other algal voodoo I do:-)

> I just know that, in
> all the years of planted tanks, this is the first time I have any
> problem with red algae.

I never had it till I brought a plant from a store that had it all over.
I got it bad for about 1-2 years and figured out to crank the CO2(to stop
it), and to remove it manually and add SAE's. Nutrients and CO2 can prevent
it from ever coming back.

> It's either due to the Onyx or the high K (or
> the higher light) since those are the things that are different.

It's getting use to all that light that is the issue I believe.
It's very common when folks, even well experienced, move up to more powerful
lighting, they have problems. Everything kicks into high gear. Dosing
regularly becomes key, balancing the tank shifts and everything starts to
get used up rapidly. It does take some getting use to. Be patient, work
stepwise, stay away from algicides/snake oils, keep up 50% weekly water
changes. Add KNO3 only after the water change(if you have a decent fish
feeding load) at 1/4 teaspoon and maybe once more during the week till the
next change, I'd still add a 1/4 of K2SO4. CO2=> I'd check it a couple of
time to make sure it's good in the range at the AM and the PM times, NO3=>
will be good to look at every 2 days for a week since that's your water
change routine and see roughly what the tank "eats"/"Produces" a week.
Traces I'd add about 10mls 2-3x a week of TMG etc. Add Amano shrimps, a
bunch and or SAE's. Better them doing the work than you.

> I also wonder if the wood is taking up too much real estate; it
> probably covers 1/3 of the tank bottom area.  Ideally, it would be
> better to have fast growers there, but I like the mossy wood...

If it's got moss/plants growing on it, it's fine.
Tom Barr

> Thanks for any comments.
> Roxanne Bittman