Fish tank hydraulics questions

[dlminehart]

My daughter has a large freshwater tank awash with floating algae. She's picked up a UV Sterilizer that'll kill the green monsters. However, it wants a flow rate of 120 gph for effective operation. The existing pump for the tank's aeration produces 350 gph. The UV sterilizer uses smaller tubing than the pump. My thought was to put a smaller diversionary circuit between pump and tank, using smaller tubing as needed by the UV device, so the pump's output would be divided into two parts. Smaller part would go through the UV device.

Questions:
1) Assuming T connectors before and after the branch, with step-down converters taking tubing size up and down as needed, would we still get the 350 gph? Or would the total flow drop? Or would flow stay the same but work the pump harder?
2) Assuming the areas of the tubing are, say, 2 units (existing) to 1 unit (branch through the UV device), would 1/3 of the flow be going through the UV?

I suspect Loring may weigh in on this, but perhaps others of you are familiar with hydraulics.

[DonHo]

Not exactly the answer you are seeking but the way I'd try handling the situation.
Algae is caused by light, sometimes it can be controlled by limiting the amount of light the tank gets, if this is not possible/or desireable I'd try one or more medium plecostomus(sp) which feed on the algae and do a good job of cleaning the tank.
DonHo

[TB Roye]

I have a couple of large tanks and some smaller ones also. There are a couple of things you can do to get rid of Algae. Do a 50% water change and vaccumm the gravel remember to refill with dechloranated water. Reduce the amount of food you are feeding. If it is a planted freshwater tank check the Kelvin rating of your lights. You do not need more than 6500k. The lights should not be on more that 10-12 hours aday, put the lights on a timer. Make sure it is not getting direct sunlight or near a window. The easiest way to get rid of Algae is to leave the lights of for a week and cover the tank. Get some algae eaters of some type. The biggest cause of algae is to much waste/food and light. A bristlenose/bushynose Plecos are and don't get over 4 inches long. SAE's are good so are Otos(don't know the scientific name) I have had a couple of Algae blooms and usually just did a partial water change, vacummed the gravel turned off the lights and sometime covered the tank for a few day. In an tank that has been set up awhile a little algae is ok it is natural and provides food for some of the fish.





Tom

[dlminehart]

We've tried these other methods during the past few months, short of putting it in the dark for days, which probably won't help the plants. The tank is in a rather dark room, and the photo period has been reduced to about 8 hours/day. The plecos and otos in there eat algae that's stationary (i.e., on the glass or gravel), but not floating stuff that makes the water into, well, very runny pea soup that you can't see more than a few inches into. The water's been tested a couple times at the local store, and shows no excess nutrients. Lights are 6500K. Water's been changed extensively and dechlorinated. Expert opinion at the local specialty fish store is to zap the pea soup. Hence my questions.

[TB Roye]

David

I have never had one get that bad, so I guess zapping it might be the way to go. The covering the tank for a few doesn't seem to hurt the plants. The only other thing would be to strip in down and start over but then you would have to cycle the tank again. Does your Aquarium shop have any idea what is causing the Algae bloom? I found that plant fertilizer can cause algae bloom also. How big a tank does you daughter have? I have found that have an Aquarium gives lesson in Biology, chemistry, ecology/environmental problems and the life cycle besides the personality issues between fish, I had one pair that I had to seperate and find a new female who would get along with male. I am getting ready to set up another 55 gal. that I picked up off Ebay for $33 with a stand. I have cleaned the tank, lot of hard water deposits and now I am reworking the stand to make it stronger and then refinishing it. I will transfer everything from a 37 and 18 gal. into the 55 when I get it all set up. Currently looking for lighting and filters on Ebay. This fish keeping is like woodworking or any other hobby you keep adding things and running out of room. I rearanged my den to make better use of the space and found I need to consolidate the fish stuff so I can keep my model building stuff in the den instead of moving it into the shop. I had to many big tools in the shop so the BT3 and miter saw station got moved back out to the garage. I have to be careful or my LOML will move me into the shop to make room for her stuff.

Tom

[dlminehart]

Tom, my daughter started with a goldfish in a plastic bag won at a carnival game stall. She escalated to a few 10 gallon tanks, a couple 20s, and a few 1 gallon ones for bettas. Then, a 55 from eBay. Finally, a 125 from craigslist, with a cabinet we part bought, part built together. No more room in the house, a gradual switch in allegiances from aquaria to digital photography, and a frustrating experience with the algae have resulted in half the tanks being consigned to the back deck, their former inhabitants sold to the fish store or consolidated in the other tanks.

You're right: she's learned an enormous amount about natural sciences, as well as about how to do research, solve complex problems, describe phenomena articulately, develop relationships with other experts, guide novices, shop for bargains, and motivate her dad to spend weekends helping her on her projects. It's more than she's learned in school, frankly, at least in the long-term useful sense.

[Russianwolf]

I'm am old hand at aquariums. Used to sell them (and fish) at a retail store and had several large ones at home. I always set them up to be self-sustaining.

My first guess as what's going on is nitite levels are too high, best way to reduce them is more plants. The more live plants (with roots) that are sucking the nutrients out of the water, the less algea you will have.

Algea will not grow in a well planted aquarium. There simple isn't enough "food" for it to live.

Once you get enough plants in there, stop feeding the fish. The fish will eat the plants and the plants will live of the fish poop.

by the way, how often and how much are you feeding the fish? Please say you are not following the directions on a fish food bottle.

[onedash]

If you have an undergravel filter get rid of it.
Since you have plants Im guessing you have good lights to sustain them. If they ar getting old the color has shifted and is doing more good for the algea than anything else. Replace with new bulbs.
Thats what did in my Reef way back when. I didn't want to spend over $100 to replace my bulbs and that along with a move and maybe a calium overdose killed almost everything.

I just wish I would have did all the research before I spent any money on that. I guess its not as easy to learn from a book though.
If I ever start over I will spend the money up front and hopefully have it forever....instead of nickle and diming my way up and wasting a lot of money.

[TB Roye]

I was just looking in my mature 55 gal. Tank and discovered about 40 Kribnisis fry(babies) Now I have to get them and mom and dad into their own tank before the become lunch/dinner for thier neighbors. Mom and Dad have them in a cave and are VERY protective. Sure wish I had that other tank ready then I could move every body else and leave the family in there. The will be going in to a 10 gal. tank that is set up for a hospital/rearing tank just got to catch them all.

Tom

[dlminehart]

Mike, nitrites are not too high. Not too many fish (about same number as were fine in the 55 gallon), reasonable amount of vegetation, a couple freshwater driftwood stumps (that wanted badly to float and took slate tiles to anchor; could either of these be problematic?), good biofiltration. Onedash, no undergravel filter, and lights are new 6500K Philips T8's. 8 of the 4' 32W bulbs for the 6'x1-1/2'x2' tank.

Tom, that's exciting about the fry! My daughter's shellies have been wonderfully productive, a month-old bristlenose pleco showed up unexpectedly, guppies spontaneously generate, but the others are not so accommodating. Angelfish spawned, but then ate the eggs, for instance.

[Pitman]

Russianwolf's advice is right on. Nitrates/Nitrites might test just fine for the fish but are feeding the algea. Best way to keep algea down in a heavily lit tank is to add lots of light loving plants, keep fish feeding to a minimum (99% of people with fish overfeed, fish will gorge themselves out of instinct, so they always appear hungry for more!). The other bit of advice I can give is to use distilled or reverse osmosis water for water changes. Tap water contains plenty of heavy metals and minerals which will feed algea (especially the blue/green slime algea) You can pick up RO units off ebay for $100 and it makes great drinking water and ice cubes too. RO water is so pure that I would reccomend using a small amount of tap water during the water change just to keep water hardness (buffering capacity) from getting too low.
Test kits are good at telling you the basic parameters for keeping your fish alive, not necessarily helping you with a truly self sufficient healthy/problem free tank.
Basic recipe for success with fresh water == underpopulate (1/2 inch of fish or less per gallon of water), feed little, good bio filter, if well lighted then plenty of plants, regular water changes with RO or distilled. Always top of with RO or dist. between water changes.
UV sterilizers should be a last resort, or used to initially gain control, then start working on the things above

Hope this helps

[gugie]

No one's made a stab at question 1, so I'll give it a shot

Pump ratings are done assuming no pressure drop on the outlet. The 350gph rating is the maximum the pump can put out. You can "derate" based on head loss, which is measured in feet, typically. There are three components: 1. Vertical head, which is the distance the pump has to push the water against gravity. 2. Pipe (tubing) loss, which you can look up in a table. The smaller the tubing, the more the loss, which makes sense. A big pump can't push as much water through a small hole as a big opening. 3. Elbow, Tee, valve, filter, etc. loss. These can be looked up in a table also.

Add all three head losses up to one "equivalent" head loss. Look up flow vs head on the pump curve that came with your unit. If you don't have the manual, you can probably look up the pump curves on the internet.

Give me an email if you need any help, I'll be glad to oblige. I have no feel for aquarium pumps, but I did sleep in a...oh, wrong thread. I did just size a pump for a waterfall we're putting in, so it's still fresh in my mind after cracking open the old textbooks for review.

BTW, you still commuting from SJ down 101?

[dlminehart]

Gugie, I could probably use your three-component method to figure out how much my 350gph pump would actually deliver through a single tube, but would that work for a tube that branched into two and then back to one again? And how'd I figure how much went through the narrower branch? I'm surprised that I've been unable to find anything on this by googling the web.

And, yes, I'm still commuting 77 miles down 85->101->156->1->68 to Monterey every day. While continuing to look for something closer to San Jose!

[gugie]

Hi David,

Figure it out assuming only one branch to see if you get the flow you want/need, anything else is gravy. If not, then I'll have to go open my old textbooks again!

Hope the SJ-Monterey drive isn't burning you out. At least some of it is through pretty country.