highly technical question

[D&RW]

issue = green water
pond size 4500 gallons
fish = 10 koi + 8 goldfish (3 of the koi are tiny, just got them for 5 bucks at petsmart. doing fine after quarantine period
plants = lillies cover 30-35 % of surface. specially designed water basket 4 ft X 2 ft X 1ft with lettuce, hyacinths and hornswort. deck shades another 10-15%.
pumps = 2. 1 easy pro 4500 gph submersible powering the easy pro large filter falls. 1 Sequence 1000 4500 gph external pump coming off the skimmer and then into a Aqua UV Ultima 2 4000 gallon bead filter. on return side is 57 watt aqua UV ultraviolet and then the water is returned to the pond via pipe that is designed to create some current around the pond.

i speced the UV light based on clarifier specs = ponds up to 5K and flow at 3250. The way i have it plumbed now the 2 in line off the pump goes into a 45 degree fitting, then into 8.5 feet of flexible 2 in pipe straight into the Ultima 2. Best i can calculate that's about 5.5 ft of head max and the resultant low at that point accd. to Sequence's chart should be about 4200. BTW, is the flow in a line the same all up and down the line after adding in the various frictional and elevations head's? or does it decrease as it goes along so it's say 4200 at the entrance to the ultima 2 but add in 6 ft of head for that and 2 ft of head for the UV and then another 7-10 ft of head for the final piping into the pond. is the flow out of the end of the pipe the same as at the exit of the pump or does it decrease along the way? if it's the same all along the way then i probably don't need to slow it down. but if it decreases along the way then i do.

so assume i need to slow it down to around 3200 gph to see if it will work better. however, in order for the ultima 2 bead filter's back flush system to work optimally it needs 4000 gph.

so, could i install a valve in the output line in front of the UV unit which is attached directly to the output of the ultima 2? I have a white brothers in-line flow rate meter i could plumb in to adjust it down to 3200. wouldn't that hurt the pump to be pumping against that pressure or no? if not, then i could open the valve to backflush and close it to the prescribed setting for clarification.

what i think i really need is a bigger UV light set to a sterilizer level of flow, but man are those babies expensive. Yikes. i simply cannot afford one right now.

thanks in advance for your ideas and input.

 

[HTH]

As you know there are two types of heads. Static and dynamic.

Static is what you can measure.

Dynamic is due to the friction in the pipe. The longer the pipe the more dynamic head you have. Each turn in the pipe introduces more friction and more head.

What goes into a pipe has to come out the other end. So if you have a total head of X just look it up in the pump table. That same rate must exist at the pump and the end of the pipe unless you T the pipe. The the sum of the two outlets will equal the flow at the pump.

The best way to determine the flow is to measure it if you can. Slip whatever size container you can under the flow and time how long it takes to fill. Anything less then a 5 gallon bucket will not give you much accuracy. You don't have to measure it at any specific spot. Where it enters the pond is a good choice and you can maybe get a garbage pail in there.

What are you nitrAte levels like ?

 

[capewind]

without making a ton of work, the easiest way to fix the flow on the uv, is keeping it on the same line BUT, install 2 T's on the line, to make new in/out lines for the UV...one with a valve on the intake side to control the flow ... this way, you still have the flow you want on the filter, just restricting the flow to the UV ...

 

[koiguy1969]

sloppy diagram but you get the idea...
the more you close the ballvalve the more water is diverted to the U.V. a second ballvalve can be installed just before the U.V for additional fine adjustment. but probably not neccessary.

 

[D&RW]

nitrates run about the lowest positive reading, what is it .15 or somesuch (don't have my equipment and cards here). it has always have read at this level. oh, that's not true. years ago when i got into trouble with my biological filter because of stupid cleaning, it read much higher briefly.

i suspect phosphates are high because the waterfall has big string algae production which i have to clean out frequently. otherwise, water parameters are pH about 8, ammonia 0, nitrites 0, nitrates 0.15, GH 3-4 and KH about 2-3. Going to bump up the latter two today because i finally found some more Morton's CaCl for the GH.

the idea for two Ts and a valve sounds easy enough. But shouldn't the valve be on the entrance side to the uv rather than inline to the outflow.

 

[D&RW]

What goes into a pipe has to come out the other end. So if you have a total head of X just look it up in the pump table. That same rate must exist at the pump and the end of the pipe

If this is true then my flow through the UV must be within flow limits for a clarifier and a clarifier must not be enough for my pond, i.e. i need a sterilizer. I do have a measuring device which I can put inline to measure the flow and will do so. my guess with all the dynamic and static head is it will be around 2100-2400 gph.

Aqua UV says their 57 watt as a sterilizer is only good for ponds up to 3300 gallons and the flow rate is about the same as for a clarifier. this is interesting because other manufactures don't make as big a deal of pond size, rather focus on flow rate. for a sterilizer the flow rate is way slower unless you have a very powerful unit.

I'm thinking about biting the bullet and buying a TMC Pond Pro 110 UV system. Cost is $400 and accd to advertising it will definitely handle my flow and pond size. anybody have any experience with these

 

[koiguy1969]

"the idea for two Ts and a valve sounds easy enough. But shouldn't the valve be on the entrance side to the uv rather than inline to the outflow"

nope... if you put the ballvalve on the U.V side youir already getting minimal flow. because water takes the path of least resistance. the majority of the water would just flow straight thru. when you close off the ballvalve the way i did it, the resistance causes the water to divert thru the first "T". .. thats why its before the ballvalve. you could plumb it so the UV is in the staight run of tubing and ball valve it. but i prefer the way i diagramed.

 

[D&RW]

fluid dynamics, even at this kindergarten level is fascinating. so, assume you have a flow of 3500 gph at the entrance to the configuration above. if you leave the ball valve open, i have to assume some of the water will go around through the uv side and more straight through. i'm sure there's some mechanical engineering formula that would tell very closely what the two flows would be. the flow through the uv would be quite diminished,; by closing the ball valve you would increase the flow to close to what it would be without the Ts minus the friction of the 2 90 degrees. so i guess i don't see how this set up would help except perhaps to try and balance the flow so the UV flow is closer to that required to be a serilizer, which is quite slow accd to various manufacturer stats. problem would be that it would be treating even less water and Aqua UV maintains that overall volume of the pond is a big factor. so maybe you're treating 15-20% through the UV. i wonder if it would keep up with normal algae growth rates.

I don't know, I may just kick back and leave it all alone. lillies are spreading and probably will cover 50% of pond surface soon. i'll increase back flushing and filter falls flushing rates to weekly. and i guess i have to believe the 57 watt uv is doing some good or i could turn it off and see what happens. another option would be to spend $400 bucks, buy the TMC 110 and hope for bathwater clarity. what a ha, ha. actually just the backflushing and filter falls cleaning did some good so maybe just doing it more frequently will be enough.

problem for me is, I'm thinking seriously about starting a handyman business for my retirement years. i'm very good at fixing things, general construction, etc. And i know a little about ponds, but i hesitate to go there because to me it is such an almost unlimited learning curve and i'd hate to have people depending on me when i am definitely no expert.

 

[HTH]

nitrates run about the lowest positive reading, what is it .15 or somesuch (don't have my equipment and cards here). it has always have read at this level. oh, that's not true. years ago when i got into trouble with my biological filter because of stupid cleaning, it read much higher briefly.

What you said might indicated you are confusing Nitr-i-te with nitr-a-te. Working bio filtration produces nitrates which can only be removed by plats with roots in the water, or water changes.

All the food you put into the pond ends up as nitrates.

 

[D&RW]

What you said might indicated you are confusing Nitr-i-te with nitr-a-te. Working bio filtration produces nitrates which can only be removed by plats with roots in the water, or water changes.

All the food you put into the pond ends up as nitrates.

i'm trying with the plants. i built a special box out of pvc tubing and screen. it's 4 X 2x 1 and in it i have flowing plants and hornswort to try and help with the nitrate issue. i realize i should probably have a lot more, but the koi just eat them up unless the plants are protected.

 

[D&RW]

I'm really frustrated ya'll. water's pea green. we've had more sun than usual this year, but the water has never been this green. and the string algae in the waterfall is prolific. now deb and i have been feeding a lot so we're going to cut back to once a day. but otherwise, i think the problem is the UV. dagnabit.

i'm not getting much help from Aqua UV. In fact in my most recent call to them the guy was rude and condescending. he had reason to be critical, i.e. i have done a number of things wrong, but he didn't have to be a jerk. and afterwards, i wrote them an email requesting specifics on how to fix my problem and they haven't responded. i don't think i'll buy anymore aqua UV stuff.

so if i slow down the flow through the UV do you think it'll help, i.e. turn it into more of a sterilizer?

 

[Fishylove]

If you have places for them, large rush grasses will compete with your "pea soup" algae for neutrients. And their extensive root systems are such the the koi really don't bother them much. So that would be a good start. But they'll need to be free roots and not in pots or this won't work. Good luck!

 

[D&RW]

thanks for the tip on the rush grasses. i'm not sure how or where i'd place them. like say, we have lettuce, hornswort and hyacinths in a 4X2X1 pvc "basked" lined with window screen with additional larger holes cut in it to allow more flow. as soon as the population of these plants exceeds the basked we're going to start distributing them among the lillies. be hard for the koi to get to the roots in those spots.

as for green water, just for grins i'm doing a backflush every day for a week. today's the second day and the initial flush was very dark. i'm hoping this will help, but if it doesn't i'm going to just grin and bear it. i know the green water isn't a problem really, i'd just like to be able to see deeper in the pond.

R

 

[HTH]

This is not for everyone but I have gone to bare root lilies. They grow rapidly and can absorb a lot of nutrients from the pond if not potted. Start with just one and see how you like it. Depot and wash the roots then place it back into the pond. Tie it to a rock or brick with bait cast fishing line if it wants to float.

There is a good chance it will develop a large root system. Just wade out with a knife and hack some of the older stuff off once a year.

If you want the lilies blooming all season leave them in pots and keep stuffing them with fertilizer tabs. The bare root ones bloom in the spring until the nitrates that built up over winter are gone then stop.

 

[addy1]

To me plants are the key to clear water. With my bog, loaded with plants, plants in the pond, I never get green water or string algae. Also water tests stay very nice.