# Help with water flow



## PARK963 (Mar 23, 2016)

Hello,

I have a 75 gallon freshwater tank. It is not planted but I do have a lot of "silk" fake plants in it. The entire back of the tank and up towards the front on the sides has plants. I also have 4 pieces of driftwood and some rocks in it as well. 

The tank has been up and running for almost a year now. I started with a Emperor 400 HOB filter as will as a canister filter. After the canister started to leak all over my floor, I was given another one by my neighbor, which also ended up having problems. Long story short...I was tired of dealing with the canisters and bought another Emperor 400. So, I now have two of those running. For the past year, the tank has housed 4 cherry barbs, 7 harlequin rasaboras, and two bristlenose plecos. I finally decided that after a year and the fish doing so well it was time to add some more fish. 

I plan on adding cherry barbs to bring the total to 9, 3 males and 6 females. I have added one pair already. My Rasabora's I plan on taking to 11 total, and have added 3 cory's with 6 more to come. The plan all along was to have a big group of corys, but I just was afraid to mess with the balance of the tank as it was thriving. 

Anyway, I am having issues with dead spots in the tank, most of which are in the back of the tank. (I also wanted to make sure the water from the left and right sides of the tanks was "mixing). With so few of fish, this was not that big of deal and I would just vacuum out the waste that was collecting. But, if I add more fish it is going to be worse, so I tried to figure out a way to increase the current in my tank. 

I tried using a powerhead placed in the back left corner of the tank directed straight across the back of the tank that I connected to a sponge. But the jet on that was so concentrated that the flow was unbelievable behind all the plants. It did manage to kill a couple of the worse dead spots in the back, but I was still having large waste dumps in the other back corner. So, I bought two Hydor Koralia Nano 240 Water Circulation Pumps. One of them I currently have in the back left of the tank shooting across the back just like I did with the power head. It does bounce slightly of the back glass. The second one is close to the back right corner and it shooting up and at a diagonal to the top and middle of the front glass. I have been very satisfied with the results as far a flow goes. The water on both sides of the tank is mixing and I have not found any dead spots. 

However, there is some serious flow going on. There are place that have very gentle flow, but other places it is still humming right along. The cherrys have been enjoying jumping the current and shooting themselves into the middle of the tank.  However, one of the new corys seems to be having a hard time finding a place to chill out. His calm and quiet corner that he would sit on a leaf is no longer that calm. I guess my concern is do I have too much flow going on? If I do, how would I go about fixing the issue? I know that all three of those fish can handle flow but I am concerned that there is too much.

I did think about getting a smartwave and alternating between the two pumps. This would still get all the dead spots worked up on an alternating basis. If this is a good idea would I still keep the pumps facing the same direction and placements that they are currently?

I did attach a picture of the tank. It is a bit different now. This is from when the powerhead was just shooting across the back. The rock on the right is no longer there. It was replaced with smaller ones in a formation. The logs have switched positions as well. I was thinking those large items in the corners might have been part of my problem. But it is pretty close. 

Thanks, in advance, for any ideas that you can give me.
Patrick


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## LittleStar (Oct 2, 2015)

Hi there,
You asked:
I guess my concern is do I have too much flow going on? If I do, how would I go about fixing the issue?

I don't know what the intake tube looks like on your systems but if it is the typical J shaped tube you can lift it up and insert something like a small piece of sponge under it so that it can't sit all the way down into the housing unit. If the J shaped intake tube isn't seated all the way down, the result is less suction on the intake, and thus less outflow and less current. That is how I have always used my hang on the back type filters.

Note that your filter tops may not fit the same way any more after doing this so you have to improvise by putting a cut of sponge under the top to balance everything but its really easy to do.

Good luck : )


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## Observer54 (Mar 6, 2016)

Some of the most healthy aquariums have mulm on top of the substrate so I wouldn't sweat it and I wouldn't add additional powerhead(s) to prevent it. Don't try and fix something that isn't broken. There's this myth we need 4x-10x gph filter flow and/or we need sufficient circulation to collect any and all debris in the filter - some think (and say) that more filtration flow is better...it's just not so...better is better. Shoot for sufficient mechanical and bio filtration so your water is (crystal) clear...and collect the mulm when you do partial water changes, or just leave it alone.


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## PARK963 (Mar 23, 2016)

Thank you for the responses. 

I really like the way things are getting stirred up with these two pumps running. My concern is that it is stirring it up a bit too much. I did place a new plant in front of the one on the right side. Seems to do a bit of blocking. 

I have another concern that with the water racing across the back of the aquarium that the debris is getting blown by the filter intakes. 

So, my next question is...what about putting them on a timer so they run for a bit everyday to stir things up and then let the filters take over?

Thanks,
Patrick


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## Observer54 (Mar 6, 2016)

You can lead a horse to drink but you can't make him water!
Sure, use a timer....but I would leave off at night when the lights are off so it's more calm when fish are resting. 
Do you already have lights on a timer???


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## PARK963 (Mar 23, 2016)

Observer54 said:


> You can lead a horse to drink but you can't make him water!
> Sure, use a timer....but I would leave off at night when the lights are off so it's more calm when fish are resting.
> Do you already have lights on a timer???


Wow, Snarky comment. Jeppers, try and ask a question and get called an idiot. 

I get the fact that you think that I should just leave it alone. I also have read people talk about having enough flow to stir everything up and not have any dead spots, which I have, which I have also read means that I run the risk of having temperature gradients.  

I was just wondering if I should shoot for the best of both worlds. 

And yes, I have the lights on a timer. I read and read and read before a started up this tank. I talked to a lot of people as well. This is something that I could not find enough information on, so I decided to ask so I made sure that I was doing things right. Sorry I asked a follow up question. 

Patrick


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## Observer54 (Mar 6, 2016)

Thin skin bruises easily, but I am sorry that I offended you. I didn't call you any names, merely that you didn't hear. I believe that we need gentle circulation but really don't need to stir things up with extra pumps. 'Normal' filtration is typically more than enough to prevent any major thermal gradients. Some dead spots or low flow regions are fine. Mulm is a natural and healthy thing and helps feed beneficial bacteria in the substrate. This is especially beneficial in planted tanks (like mulch in the garden).
You're convinced you need to stir everything up, so be it. Nuff said.


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## kedi (Dec 24, 2015)

Maybe try and add tubing to the filter intakes, to get them into the two back, bottom corners. Move the filters as close to center as possible. See if the filter flow alone can scavenge all areas.
It is unlikely that you can get everything to flow. That would be a pretty lively flow overall. Some fish would love it.

My 55 gallon with a Fluval 306 has quite a good current through most of the tank. But a couple spots are fairly dead. Plants at the intake end also diffuse and slow the flow. You will always have deader spots in corners and around decorations etc. Just have to vacuum up more there. I actually have a bonus somewhat dead spot, where nasty stuff collects for easy vacuuming.


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## aussieJJDude (Jun 9, 2012)

I understand how you feel. In normal planted tanks, the plants would utilise the waste not to mention as they grow in they will help block some of the flow. However, since your tank is all fake plants, the chances of them growing in is non-existent! ;-) 
The best bet would be to put the powerheads on a timer. A suitable example would be to have them running throughout the day and at night, turn one or both of them off to give some of the less active species a chance to rest. 
Or have them alternating throughout the day and then turn one/both off at night! Do the setup that works for you!
However using decor such as rocks, wood and plants will give them places to rest.... So maybe pack the tank a bit more, using this as an opportunity to go on a shopping spree and buy a lot of pointless things (been there, done that! It's rather fun too!  Plus a good excuse.)

*Ramble warning...*
The thing that baffles me is that most of the species you have are found in places where turbulent water can occur. The streamline fishes - barbs, rasboras - often swim in places where there is a lot of flow going on, which their streamline bodies and forked tails help reduce drag. And the cories and BN have adapted to turbulent conditions (sucker mouth and flat "tummies") where they can hug the substrate, as the bottom of a river can me the most turbid. The only species where I can remember where they normally found are the platies, however they are rather bulky so I'd imagine they do better in calmer areas. How are you platies faring?

Maybe let the fish get use to the sudden "influx" of water movement? Could be just that our pet fishes are so use to the dealer's tanks of air stones and air driven filters they are "weaker" than the wilder brother/sisters. A chance for them to build up their resistance might be the only thing you need?


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## Observer54 (Mar 6, 2016)

I guess if the objective is to simulate a river (like some reef tanks simulate the surf) it would make sense to power drive water lengthwise through the tank. Even though for display, I prefer the calm lake/pond effect.

However, I think sometimes folks get caught up in thinking they need excess flow to 'clean' the substrate of any/all detritus/mulm that might collect there....and some of these same folks might not service their filters for a month or more creating quite the nitrate factory!

I'm remembering in my youth my mother had a 5 gallon slate bottom aquarium. With only a bubble up filter (yes it was that long ago) and some floating anacharis. The tank rarely saw a partial water change and always had a good layer of mulm on the bottom....BUT the water was crystal clear and the fish were all large and very healthy!

I'm also (after some 40 years in the hobby) thinking of the prevailing myth that we need to filter the tank water volume 4 to 10 times per hour! It seems to me that good filtration isn't about how much water is pushed through media, but how well the media traps and removes contaminants....and filtering every drop a couple of times every hour should be plenty!

Note: It is worth mentioning that coarse gravel substrates can be a problem as uneaten food and detritus gets trapped down below and much like the unserviced filter, in the absence of routine gravel vacuuming, becomes a nitrate factory.

Just my $.02 (and here I had 'said' " 'nuff said' ")


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