# Frequent water changes & algae growth



## niko

Following Freemann's example I started doing daily water changes to 2 of my algae infested tanks. The tanks where not dominated by the algae but there were enough of them to try to change the situation.

The reason I post this is because I noticed that daily water changes in both tanks affected the algae (including BBA!) in a negative way - they either didn't grow at all or stayed static. Plants on the other hand bubbled heavily in both tanks and grew very well.

Tank 1 (18 gals. tall);
--30% daily water change using 100% RO
--Plants: Ludwigia brevipes, Juncus repens, Wisteria, Stargrass
--Substrate: FertiPlant (rich substrate) covered with quartz
--Light: At least 4 wpg (96 watt quad Coralife)
--Parameters: NO3=2-4, PO4=0.5-0.1
--Fertilizing: Daily PF and Fe/TE (PPS fertilizers)
--Fish: None

Tank 2 (Oceanic 30 gal cube)
--15% daily water changes using 100% RO
--Plants: Java Fern, Bolbitis
--Substrate: Inert gravel
--Light: 3.5 wpg
--Parameters: not tested
--Fertilizing: Daily PF and Fe/TE (PPS fertilizers)
--Fish: 10 small tetras, two 2" angels

Tank 1 didn't neede very little additional of Phosphorus. It took 7 days for the PO4 to get from 0.5 to 0.1.

Tank 2 has 2 kinds of heavy bubbling plants. Tiny additions of P (2 mls. of PF) result in considerable bubbling. The tank is probably P deficient despite the presence of fish.

An interesting observation was that Tank 2 develops algae on the glass if I discontinue the daily water changes for 2 consecutive days. Resuming the daily water change suppressed the development of these algae in this tank.

Tank 2 developed bacteria followed by green water and is currently blacked out.

--Nikolay


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## Edward

niko said:


> Tank 1 (18 gals. tall);
> --Parameters: NO3=2-4, PO4=0.5-0.1
> 
> Tank 2 (Oceanic 30 gal cube)
> --Parameters: not tested


Hi Niko

It is quite difficult to compare the tanks and discuss the situation without complete analysis. Are you planning on the water parameter testing the Tank 2?

Thank you
Edward


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## Laith

Nikolay, you don't mention anything about CO2 fertilization in either tank.

Water changes usually bring additional CO2 to a tank. Lack of enough CO2 in a higher light tank is often a cause for algae, as is a lack of any nutrient.

If that is what's improving the conditions and there *is* CO2 injection in the tank, it usually means the CO2 concentration is not high enough and needs to be increased.


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## niko

My post is not too precise in the details but what I wanted to stress was the observation that daily water changes did suppress algae.

I finally tested the cube tank - NO3=1-2, PO4=traces. 

Laith, both tanks have pressurized CO2 and minimal surface movement. I haven't checked the level of CO2 but it must be rather high (>35) because of the rate I inject the CO2, the size of the tanks, and the use of RO.

--Nikolay


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## Cavan Allen

I suppose that if you changed enough water, a significant number of algal spores might leave along with it. I don't really know how much that would help.


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## niko

Well for all it's worth every day, in both tanks the water that I sucked out had a tint - yellowish in Tank1 and greenish in Tank2.

--Nikolay


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## Laith

Could it be that simple? that daily water changes remove algae spores before they become too much of a problem?

I guess that could make sense.

But if that's the case it sounds like it would be a constant competition between how often/regularly you can do a water change and the speed of propogation of the algae.

Therefore if you can slow the rate at which the algae is propogating, the daily water changes will have less of an effect? Comes back to the notion of not letting the tank get any nutrient deficiencies...


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## plantbrain

If you stress the algae prior, causing them to release spores, then do the water change, then you will get better results with this routine.

Spore inducement will occur within hours in several green algae.
Temp, CO2, dark, etc will cause them to produce spores. 

Work on the tank and trim, prune, clean filter etc and then do a water change at the end.

You can use NH4(0.4ppm) if you do daily large water changes and NOT get algae.

Regards, 
Tom Barr


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## defdac

If they produce spores in darkness it would be smartest to do wc:s before lights go on/ in the morning?


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## plantbrain

D-
It does not matter. They will respond to any radical change(temp is a good one).

Also D, you sent an abstract on Oscillitoria fixing N2 gas, I reviewed the article. The species in question is a marine species and they group together to form a low O2 environment. This is common in other genera.
Does it apply to our species? No, I think no matter what, we are a long way from becoming N limited.
Organic matter is also correlated well with BGA, OM possesses a good deal of N in bound forms. as it breaks down, N is released and mulm is a good source.

Too much mulm can cause algae in many tanks depending on the loading an dhealth, biomass of the plants. We commonly see BGA allong the gravel lines. 

Sorry to be off topic here, just wanted to let you know I was noty ignoring ya.

Regards, 
Tom Barr


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## Edward

Laith said:


> Could it be that simple? that daily water changes remove algae spores before they become too much of a problem?


Then how do we explain algae free tanks without water change for a long period of time, months and years?

Edward


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## plantbrain

Edward said:


> Then how do we explain algae free tanks without water change for a long period of time, months and years?
> 
> Edward


Good plant growth => supresses NH4+, something you cannot test for without using N15 labeled NH4+. NH4+ gets used up before we have a chance to test for it. Stable isotopes are very useful in following the nutrient flow. Unless you add it on purpose and are looking for an algae response, you often miss the pulse of NH4 as it's removed by plant and bacteria conversion rapidly but is enough to induce an algal bloom.

You also assumes a stable system for the plants. Not likely with all the algae presence occuring.

Unlike testing, algae and plants never lie.
They are the ultimate test of the environmental conditions and so useful that we and the EPA use them as bioindicators.

But once induced by a number of environmental conditions depending on the species, the adult established algae, much like any invasive species, it is extremely difficult to root out once it is well established.

Adding enough plants from the start and packing the tank, adding herbivores, pruning, makes it difficult for the algae to establish ever. Lower light also helps a great deal and relieves the CO2 and nutrient demands for the plants which need far more nutrients and CO2. Algae need more light to drive their DIC carbon needs from -HCO3 efficiently also.
There are a few other issues as well.

I have tanks with 2+ years without a water change.
So do others.

I agree that CO2 is the significant issue here, test kit or not. 
BBA does not appear without some variation in the CO2 level and can hang on afterwards for a long time unless removed even after correcting the CO2 level.

High O2 levels can cause issues with spore settling rates and fecundencity certainly, but my test showed that the algae species changed some, yet the algae biomass remaind the same under a number of CO2 and O2 combinations.

Spore removal alone is the not the reason.
There are other factors as well involving organically bound nutrients and loading.

Regards, 
Tom Barr


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## timdz

I am curious as to why we haven't inquired about what the dKH and pH is in the tank, or why it hasn't been posted. 

Even measuring pH fluctuations throughout the day. If possible please post pH and dKH readings... it might help to understand your situation a bit better (at least for me,)

-Tim


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## defdac

plantbrain said:


> The species in question is a marine species and they group together to form a low O2 environment. This is common in other genera.
> Does it apply to our species? No, I think no matter what, we are a long way from becoming N limited.
> Organic matter is also correlated well with BGA, OM possesses a good deal of N in bound forms. as it breaks down, N is released and mulm is a good source.
> 
> Too much mulm can cause algae in many tanks depending on the loading an dhealth, biomass of the plants. We commonly see BGA allong the gravel lines.
> 
> Sorry to be off topic here, just wanted to let you know I was noty ignoring ya.


Thanks Tom! I saw the response regarding N-fixation at www.barrreport.com too!


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## plantbrain

You can add NH4+ and see how algae respond in a stable tank with good plant growth. 
Do this in a range that will show variation.

0.1ppm
0.2ppm
0.3ppm
0.4ppm
0.5ppm
0.75ppm
1.0ppm

Don't add fish

Wait one week for the response time, typically it'll occur in less than 2-3 days, seldom sooner than one day.
Thus the response needs some time, but it's about 12-48 hours.

Then repeat with NO3 and/or different concentrations.
Then try Urea
Next repeat this by adding progressively more and more animals, shrimp are useful, eg Ghost shrimp.

You need to clean out the algae that was from the last test or have several tanks each time, so this takes a few months to do.

Something few aquarist do. How many folks here are willing to trash their tanks for a long peroid of time?

Not many.

But to that end it answers questions and says why too many fish = algae wereas excess NO3 does not.

If you relied solely on test kits for measurements, you'd likely never see the relationship between NH4, NO3 and algae.

pH and alkalinity are adressed, CO2.
Which is about 90% of the problems folks have with algae.

So what occurs with non CO2 tanks? Same darn thing. Just lower levels of NH4, NO3 and CO2. As long as a non CO2 tank is stable in terms of low CO2 and nutrients(relatively easy by *not* doing water changes), the plants adapt by increasing the amount of Rubisco in the leaf to obtain more CO2 to reduce into triose and hexose sugars.

If you do not need it at high levels of CO2, why make extra?

What happens if you bob between high and low daily or over the course of a few days?

Algae. They respond faster than plants.

Regards, 
Tom Barr


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## niko

Tim,

Both tanks had KH of 1 to 2 because of the RO water. The pH was in the range of 6.2 to 6.5. Both tanks have the filter outlets discharging under the surface.

In Tank1 the CO2 has always beein running almost full blast from a pretty big diffuser - picture of the same diffuser. "Full blast" means that any further increase of the pressure would produce bigger size bubbles. I have no explanation why the pH doesn't go lower than 6.2 with KH of 1.

I stopped the crazy daily water changes in Tank1. Now it has healthy, fat BBA but no other algae. The plants are growing extremely well.

Tank2 doesn't get daily water changes either. Green algae are abundant.
The ferns bubble pretty heavily.

--Nikolay


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