# powerheads, circulation, and CO2???



## lowfi (Apr 18, 2007)

Hey everyone,

I have a 20H with a Rena XP1 on it. The Rena cycles 250 gph. I have the outflow of the pipe flowing almost totally open to make sure circulation through the tank is good. I am also banking this outflow off of the side glass, so that the current hits the bubbles coming up from my diffuser (which is in the front, on the same side as the outflow pipe). I did this to blow the bubbles that are just about reaching the surface back down, and this disperses the CO2 bubbles throughout the tank. I have been having some algae issues with BBA/staghorn algae and now some hair algae, and thought that it was my circulation through the tank. Would I be better off to lower the flow through the outpipe, and add a tiny Rio powerhead, or just continue what I am doing. If I decided to add a little powerhead, should I put it right above the diffuser so that the bubbles coming up from the diffuser get sucked in and shot right back out to the other side of the tank??? If I purchased the powerhead I would have to decide where to put it, and then I would have to change the direction of the outflow pipe. I noticed in pictures of ADA lily pipes, everyone has them pointed directly accross the tank. Would it be bad to have the outflow shooting across the tank, with the powerhead on the other side of the aquarium, pointing back at the outflow? Would this create a "wall" of water in the middle where the two currents meet? I was hoping that this outflow setup would help spread out possible "pockets" of nutrients and spread out the CO2 better. So far I cant tell if its working. Would I be better off to have my outflow pointed across the tank instead of blasting towards the side adjacent to it and circulating water around? Sorry, this post is all over the place. Thanks for any help you can give, I understand if you cant. I can get a picture up if you want.

Cheers,
Sean


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## Glouglou (Feb 21, 2006)

A good circulation is good and help the plant get their nutrient (Prandtl boundary). To much circulation or agitation of the surface will loose CO2.

Having your CO2 going in your power head is a good idea. My reactor it’s just that, but I add a home made limewood (basswood) diffusor to my CO2 line to have micro bubble goin in. To the exit of the PowerHead / reactor I restrict the bubble down.

Work perfectly


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## NoSvOrAx (Nov 11, 2006)

The rena xp1 will only do about 100gph or so with media in it. I have xp4s and they only get about 190-200gph or so with media.


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## hoppycalif (Apr 7, 2005)

Not everyone is agreeing that you must have good water circulation throughout the tank. But, I think that is the case. Unfortunately, I don't know of any rules of thumb on how to do that. And, however you do it, if you don't prune regularly to keep the plant mass down, you soon lose much of the circulation.


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## houseofcards (Feb 16, 2005)

I_ have been having some algae issues with BBA/staghorn algae and now some hair algae, and thought that it was my circulation through the tank._

Trust me circulation is not your problem. Thos algaes grow in locations where circ is strong or weak. If you have an out-of-the box 250gph filter on a 20g you have more than adequate flow IMO. Even if it's only 100 effective gph that's 5 times/hour turnover. What is that tank two feet wide, no way the co2 isn't being distributed.

Control your light duration and control the organic content and you will kiss your algae problems good-bye.

What is your lighting schedule, feeding, fish load and water change schedule?


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## lowfi (Apr 18, 2007)

thanks everyone for the responses....

for my light duration...i run 8 hours of 48 watt T5HO lighting a day. I only inject CO2 when the lights are on (well actually no, I turn the CO2 on a little before the lights come on, and I turn the CO2 off right after the lights go off) I only have 1 dwarf puffer in the tank, and I hardly ever feed him. My fertilization is PPS-PRO. I dose 2 mls. of macro and 2 mls. of micro a day, but am thinking about dropping down to ~1.5 or 1 ml. per day due to algae problems. With PPS-PRO water changes are not a big deal, but I tend to do 25% once a week (sundays). Ooops I almost forgot that I also have 3 amano shrimp in the tank. I am thinking about adding 10 more amanos and 3-4 ottos (what do you guys think? 3-4??) I did a big trim so circulation should go back up. What do you guys think about changing my outflow from shooting towards the front of the tank to across the tank? 

Thanks again,
Sean


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## hoppycalif (Apr 7, 2005)

PPS Pro starts out as a relatively lean fertilizing method, so you are not causing algae by dosing per that system. Reducing the amount of fertilizers is more likely to make the algae worse rather than better. You fight algae by getting the plants growing well and healthily, and that takes nutrients.

You should be able to see the water circulation in the tank if you watch carefully. Watch where the leaves sway in the water and what direction the water comes from to do that. Look for areas where the leaves don't seem to move - no circulation. If your fertilizers make a small cloud of different index of refraction water, as mine do, you can watch the motion of that for various places you dump it in the tank to see how the water moves there. All of that, together with what logic tells you based on how the water should move to get from the filter outlet to the filter inlet, should enable you to figure out how to make it better. It isn't easy.


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## lowfi (Apr 18, 2007)

thanks hoppy!


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## houseofcards (Feb 16, 2005)

_With PPS-PRO water changes are not a big deal_ 
What from a fert standpoint? How about the organic build-up in the water column. Whether ther organic build up be from dead plant leaves, food or waste. It will be larger in a tank without large water changes. So your running high light all day and not doing big regular water changes. This in my opinion is your main issue not flow. Your running a 250gph filter on 20g, I'm running a 158gph filter on a 72g and a 116gph on 46g. Leave the powerheads to the saltwater folks.


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## lowfi (Apr 18, 2007)

ok sweet. thanks for pointing that out. what supposedly is the deal with pps-pro is that youre using minimal amounts of fetilizers, just the bare essentials to get by. by the end of the day, your plants have used all of this up, so water changes arent necessary at all. BUT this is what ppspro recommends, i dont do this. I do 25% a week. I dont have very much build up from food or waste, but i think that I will now do bigger water changes every week~1/3 or larger. thanks a lot.


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## FacePlanted (Aug 13, 2007)

Make sure you are not limiting your plants in any way (co2, ferts, too much light) either.

Do you use tap water? If you do, wouldn't it be just as easy to do a 50% or larger water change? Wouldn't that be better for knocking back that algae and for reducing the DOC of the tank--which seems to me like a big cause of algae?

As well as waterchanges and low DOC, I do think that circulation is really important to keep adequate. It really helps keep nutrients supplied and co2/mist evenly distributed. Leaves swaying in the current seems perfect to me.

Both of these things/methods(circulation & larger WCs) will work well to fight algae, especially when used TOGETHER. The more prongs to your attack, the more effective you will be.

Adding Excel is another "prong" you can add to your attack that will hit the BBA and maybe even the staghorn. Higher doses and direct applications has eventually worked against staghorn and bba for me personally.

Good luck "winning the war" 
-Mike B-


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## houseofcards (Feb 16, 2005)

I don't want it misinterpeted. A certain amount of flow is good, but I think many times it's exaggerated how much you need. I'm not making a general statement, but instead talking about lowfi's tank. He has plently of flow with that filter. It's only a two foot tank. I would be shocked to find that your co2 concentration is less on one side vs the other because of flow.


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## lowfi (Apr 18, 2007)

good point houseofcards. it is not a very big tank. we are not talking 120 gallons here. my leaves are now "blowing in the wind" I think that it is enough flow for the tank.

FacePlanted: what's DOC? i dont think that I have ever seen that acronym before. do you mean dissolved oxygen (DO), dead organic matter (DOM)? I apologize if it is obvious and I missed it. About excel... I have been dosing excel at 5mls a day in the morning. I think that it will help but I am trying to get to the root of the problem. I would really hate to run out of excel and have an explosion again of algae once the bottle runs out or when I stop using it. That would be depressing to say the least.

heres a pic of my tank:









The outflow is on the lefthand side of the pictures, pointing towards the front but angled against the left side panel of glass. The flow then hits the bubbles and drives them back down and around the tank. I can actually see little bubbles get sucked up in the inflow on the right. My biggest problem with algae is on the dwarf sag. leaves, and some of the grass has BBA on the dead stems. When I trimmed my grass a while ago, a lot of it didnt grow back and turned brown. This is what is collecting the most bba. Some of that red ludwigia arcuata is also getting some BBA problems and the stems actually look really dark(lower stems look almost black. I did a huge trim yesterday to remove some of the homlier plants, and am going to do a water change today) I scraped some algae along the grassline down low near the substrate. The dead stems are hard to remove without ripping the whole plant out, and snipping tends to snip good stems too short. Any tips on how to remove algae in tight places would be cool...I was starting to dose H2O2 on the grass but stopped.

ABOUT MY BLYXA! I planted it on the right and you can see the largest bunch near the middle right. From everyones pictures I see on here, their blyxa gets large, rubust, and the plant leaves get long. I can never tell the scale of the leaves on members photos but they look ~5" or so. I planted my blyxa and all it does is send new little micro plants with ~1.5" neon/bright green leaves. Should I trim these off and replant? I want those bigger bushes. There actually are some little blyxa plants on the right that I planted that honestly don't look like they've grown at all. They are healthy looking but will not grown any taller.

Thanks for the responses, i appreciate it!

Sean


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## lowfi (Apr 18, 2007)

hoppy,houseofcards,nosvorax, everyone! what do ya think?!


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## hoppycalif (Apr 7, 2005)

I didn't respond because I can't see what the problem with the blyxa is. When I had good success with it I had 2.5 to 3.5 watts per gallon of AHS light kits, with EI dosing, CO2 at about 30 ppm, and as I recall I had CO2 mist going at that time. I quit using that plant after I added 3 Yoyo loaches, and caught them nibbling the growing heart out of the plants. They had all of my blyxa plants stunted down to little nubs. I think the secret for growing that plant is high light, heavy fertilizing and high CO2 ppm, with CO2 mist making them do the best.


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## houseofcards (Feb 16, 2005)

Certain plants for whatever reason don't always grow in everyone's tanks even when it appears you are providing all the necessary ingredients as Hobby prescribes. Some plants are just funny that way and it probably doesn't pay to chase the reason why and have a change ruin something else, especially since you have a nice tank. It's far easier to replace the plant with something else. I believe Blyxa to be one of those funny plants and there are others. I've not been able to grow it very full under 3.6wpg on a 72g, with heavy co2 mist, heavy ferts, etc. while I've seen others grow it quite full under much less light.


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## lowfi (Apr 18, 2007)

Yea well if thats the case ill be really bummed out. I wanted to plant behind the front rocks and fill that in with nice blyxa bushes. I just dont think I have enough light our something. well at least that is a little comforting. you like the tank? I just did a huge trim to up the flow, i think it will be nice. Im bummed there isnt more room behind the main rock on the left. Thats why there isnt any plants back there, the rock is too thick. I filled it in a little at the trim so hopefully it will look better in the future. Question: when you trim your plants, do you just chop it straight across? thanks


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## houseofcards (Feb 16, 2005)

lowfi said:


> Yea well if thats the case ill be really bummed out. I wanted to plant behind the front rocks and fill that in with nice blyxa bushes. I just dont think I have enough light our something. well at least that is a little comforting. you like the tank? I just did a huge trim to up the flow, i think it will be nice. Im bummed there isnt more room behind the main rock on the left. Thats why there isnt any plants back there, the rock is too thick. I filled it in a little at the trim so hopefully it will look better in the future. Question: when you trim your plants, do you just chop it straight across? thanks


Well if you take that Rotala group on the left behind the rock, I would trim in the shape of the rock so a little lower in the front and then tallest in the mid back and taper it on the sides a bit. I would trim about alittle lower than half way down the length of the stem now. The regrowth will be bushiner and look fuller.


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