High or low current in a high-tech tank? - Tropical Fish Keeping - Aquarium fish care and resources
 
LinkBack Thread Tools
post #1 of 7 Old 01-18-2012, 05:39 PM Thread Starter
Member
 
DKRST's Avatar
 
High or low current in a high-tech tank?

Is high or low current better in a planted tank or does it matter? I have seen responses both ways. Low current to mimic slow-flowing river tributaries some fish are native to and to reduce CO2 loss. High current to reduce algae and improve CO2 and nutrient distribution.

Does the current matter if there is good circulation? Why would higher current help prevent BBA, as mentioned in some posts?

55 planted, medium light, EI dosing, pressurized CO2.

18 species/varieties of fish, 15 species/varieties of plants - The fish are finally ahead of the plants!
*560 gallons (2120 liters) in 5 tanks -> you do the math.
DKRST is offline  
Sponsored Links
Advertisement
 
post #2 of 7 Old 01-18-2012, 06:10 PM
Member
 
bigfish93's Avatar
 
Quote:
Originally Posted by DKRST View Post
Is high or low current better in a planted tank or does it matter? I have seen responses both ways. Low current to mimic slow-flowing river tributaries some fish are native to and to reduce CO2 loss. High current to reduce algae and improve CO2 and nutrient distribution.

Does the current matter if there is good circulation? Why would higher current help prevent BBA, as mentioned in some posts?

55 planted, medium light, EI dosing, pressurized CO2.
I believe this decision ultimately comes down to the type of fish you have. If the fish prefer calm water with little to no current, then try to have minimal current in the tank. If you have fish that prefer a current, then create a light current in the tank. A current in the water would spread the nutrients around, but if they are being spread around to fast, then I don't think the plants would get a chance to use them. You also have to remember that there are thermal currents, the fish swimming and moving the water, and obviously there will always be a little current from the filter.

Advice for anyone new to the hobby: Do your research!! Before you do anything to your aquarium, take some time to research it. It has made a huge difference for me

S.A. Flooded Jungle (20 gallon)
A heavily planted tank. Inhabitants include: 7 Lemon Tetra, 1 Whiptail Catfish, and MTS.
bigfish93 is offline  
post #3 of 7 Old 01-18-2012, 06:39 PM
Member
 
lorax84's Avatar
 
it all depends on the plants you keep but most species of plants prefer low current.
lorax84 is offline  
post #4 of 7 Old 01-18-2012, 07:04 PM
Member
 
Byron's Avatar
 
Circulation and current are two different aspects of water movement. Fish have differing needs with respect to current, and I believe that should always be foremost in deciding water movement. Won't say more on that since you've specifically asked in respect of planted tanks.

Circulation is important with respect to plants. Water movement removes particulate matter that settles on the leaves, it distributes nutrients to the leaves and roots, and a flow through the substrate is essential. It also ensures a more even temperature throughout the tank, though I suspect this is really only an issue when there is an extreme outside the tank.

One can have a healthy planted tank with no filter, thus relying solely on thermal currents and fish swimming to achieve the circulation. This is generally sufficient for the plants; if not, such a tank would not work, and they clearly do. Which brings us to consider if there is some point at which more current is detrimental, and this is where opinions differ. My own is that water flow should be suited to the fish, but no more, and minimal for this purpose is best.

Hiscock [Encyclopedia of Aquarium Plants, p. 116] writes that "mountain streams...are inhospitable places for aquatic plants. Fast-moving water constantly batters the leaves and removes useful nutrients, while high oxygen levels make life hard for many plants. ... CO2 systems would be ineffective in this type of aquarium, as the increased air/water exchange would remove much of the CO2 as soon as it was introduced." High oxygen levels make it difficult for plants to assimilate nutrients.

Walstad [Ecology of the Planted Aquarium] advocates much the same, supporting this view with scientific studies. CO2 diffuses very slowly in water, about 10,000 times slower than in air. And it takes aquarium plants four times longer to assimilate CO2 submersed than it does in the air (the aerial advantage). So the more rapid the water current, the less carbon will be taken up by the plants, and at the same time the more carbon will be lost through the gaseous exchange increased by spraybars, airstones and wet/dry filters. In one experiment, water movement of 1cm per second stimulated photosynthesis in Callitriche stagnalis, but faster water movement at 4 cm/second decreased photosynthesis by 13-29%. This is fairly significant.

Byron.

Byron Hosking, BMus, MA
Vancouver, BC, Canada

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian. [unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]

Last edited by Byron; 01-18-2012 at 07:08 PM.
Byron is offline  
post #5 of 7 Old 01-18-2012, 07:30 PM Thread Starter
Member
 
DKRST's Avatar
 
Very interesting numbers Byron, thank you. And thanks to all others for your responses as well!
Definitely different opinions on TFK than on another forum that focuses on plants! I never understood the logic about "more flow (and circulation) is necessary in a high-tech tank". The high-flow school of thought never made sense to me, always seeming counter-intuitive. I can see some slight current/circulation helpful to help move dissolved CO2 and nutrients around, but nothing near the velocities some people advocate.

18 species/varieties of fish, 15 species/varieties of plants - The fish are finally ahead of the plants!
*560 gallons (2120 liters) in 5 tanks -> you do the math.
DKRST is offline  
post #6 of 7 Old 01-18-2012, 07:35 PM
Member
 
Byron's Avatar
 
Just noticed I missed the algae and high current point. I have also read that increasing the water movement is one means of combating brush algae. I've not done this, and have no intention of doing so, as the current would annoy my fish (and plants if one accepts that view), but I have to question it; I have brush algae on the filter tubes in the tanks with canister filters, where water movement is fastest. This would seem to contradict.

Byron Hosking, BMus, MA
Vancouver, BC, Canada

The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian. [unknown source]

Something we all need to remember: The fish you've acquired was quite happy not being owned by you, minding its own business. If you’re going to take it under your wing then you’re responsible for it. Every aspect of its life is under your control, from water quality and temperature to swimming space. [Nathan Hill in PFK]
Byron is offline  
post #7 of 7 Old 01-19-2012, 10:35 AM Thread Starter
Member
 
DKRST's Avatar
 
Quote:
Originally Posted by Byron View Post
I have brush algae on the filter tubes in the tanks with canister filters, where water movement is fastest. This would seem to contradict.
Ditto, I have some BBA growing there as well. Evidence doesn't match the "high-flow" advocates at all!

18 species/varieties of fish, 15 species/varieties of plants - The fish are finally ahead of the plants!
*560 gallons (2120 liters) in 5 tanks -> you do the math.
DKRST is offline  
Reply

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
75g High Tech Help trit0n2003 Beginner Freshwater Aquarium 3 12-07-2011 11:08 AM
high tech ten gallon plan Jwest Beginner Planted Aquarium 14 04-30-2011 11:23 PM
Changing from High tech to low light migdem Beginner Planted Aquarium 29 04-27-2011 04:27 PM
New high-tech nano Redknee Beginner Freshwater Aquarium 5 10-29-2010 05:30 AM
Based on number of fish, will a low tech tank have to go high tech? firetyger Beginner Planted Aquarium 3 10-10-2009 02:56 PM

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome