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building a small fish pond


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#1 chrisusvi

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Posted 18 September 2009 - 11:19 PM

I'm building a small fish pond 4ft. by 6.5ft. About 3 cinder blocks tall. With a pond this small, what type of water care would I need? I have 3 fish that are growing fast. I have them in a 30gal. tank. The fish are about 5-6 inches long. I am installing a drain in the bottom slab for easier cleaning. Do fish eat mosquito larve?:banana:
I live in a hot and humid climate and the pond would be in the direct sun for a few hours a day. Is there something I should do about that?

Any advice would be appreciated.

chrisusvi:coolgleema:


#2 koiguy1969

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Posted 18 September 2009 - 11:29 PM

6.5' x 4'x 2' x 7.48 = 390 gals...i would build a 30 gal + biofilter and run a pump of 500 to 700 gals an hour .. there are plans for very good bio filters on this site.. in the DIY and EQUIPMENT forums "koiguys 55 gallon bio filter"and the doc filters or if you preferr a lower profile i show how to build a 70 gallon stocktank filter too.. all these filters are of a high quality...cheap,easy to build, and out perform any store bought you can get for anywhere near the money... just down size them to a sturdy 30 gal outdoor plastic trash can..if you want something smaller.
theres definately something fishy about this forum!

#3 chrisusvi

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Posted 19 September 2009 - 09:20 AM

I'm planning on adding more fish too. Is there anything solar powered (filter-wise)? I don't want to deal with running electrical lines.:banana:

#4 koikeepr

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Posted 19 September 2009 - 12:53 PM

There is nothing on the market solar powered that is strong enough that I've seen. If you wanted to use these, you'd have to buy panels and rig it all up yourself. Question is, where would you put the panels that have to be in plain sight to collect the sun's energy.

Also, filtration must run 24 hours per day or you lose the good bacteria your filter media has built up. That doesn't really correspond with solar power, unless you have batteries collecting the sun's power.

Will be much easier with electrical unless you have the capability and space to deal with solar mechanicals.

#5 chrisusvi

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Posted 19 September 2009 - 03:00 PM

Before I pour the concrete slab would I need to include an electrical pipe or would the filter be somewhere else? Do I just need a curculation pump? I'm putting a drain in the bottom for easier cleaning too.

#6 koikeepr

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Posted 19 September 2009 - 03:54 PM

good choice on a bottom drain, but you still need a pump and filter nonetheless. For your size pond you wouldn't need anything very big or expensive. Do you have a budget? Laguna pumps and filters are very good and long-lasting. They also are very low when it comes to energy consumption in comparison to other units.

The smallest Laguna Max-flo 600 will work for you (as it moves 1200 gallons of water every hour). Am not sure if you're interested in DIY'ing a filter yourself--as this is the best and cheapest route. But if not, filters such as the Powerflo 1000 External Bio filter, or the Pressureflo 700 would be fine for you. I'd go with the Pressureflo if you could, as it's really easy to clean.

But as others have said here, there are plenty of filters described on this site you can build yourself as well.

#7 chrisusvi

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Posted 19 September 2009 - 05:56 PM

I don't need to any electrical pipes in the slab then. The pump and filter are on the top?;)

#8 koikeepr

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Posted 20 September 2009 - 12:59 AM

huh? I don't get your query.

Where is your closes electrical outlet? And hyes, depending on what you do the filtration/pump can all be above ground. Yes.

#9 chrisusvi

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Posted 20 September 2009 - 12:23 PM

I'm making the pond out of concrete blocks so I had to pour a concrete slab. I was wanting to know if I needed to stub out an electrical pipe for a pump.

I calculated that this, I guess I can call it a tank, will be approx. 165 gallons.

Does the Laguna Max-flo 600 filter need anything else to go with it?
I saw in the installation diagram that a tube ran from the Laguna Max-flo 600 to another box outside the tank?
Would I really need the size filters that were recommended? It's only 165 gallons.

#10 koikeepr

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Posted 20 September 2009 - 02:12 PM

I thought koiguy said it was 390 gallons? How are you coming up with 165 gallons based on your early measurements? Koiguy's calculations seem correct. I don't think you're multiplying everything by 7.5 to come up with the volume calculation...

The Laguna maxflo has a flow rate of 600 gallons per hour, so if your pond is 390 gallons that would be the minimum you would want to have for a pump. In terms of filtration, you always want to have as close to twice what you actually need, so the filters I recommended are correct as well. The more filtration the better--better to go bigger than be undersized.

The install diagram is showing you install options that are possible. All you'd need is one maxflow and one of two filters I mentioned. That's it.

#11 koiguy1969

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Posted 20 September 2009 - 02:55 PM

my calculations are correct.. cinder blocks are 8"x8"x16" so 3 corses are 24"(25&1/2" with mortar)...6.5' x 4' x 2'= 52 cubic feet x 7.48 (which is how many gals 1 cubic foot holds)=389 gals to be more percise. where you got a 165 gals i just dont know..
theres definately something fishy about this forum!

#12 koikeepr

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Posted 20 September 2009 - 04:52 PM

I agree koiguy. It's a common mistake that folks just multiply the measurements without using the 7.5 multiplier.

For those interested in how you calculate pond water volume in the USA, here's the math:

In order to determine how many gallons of water your pond holds, you need to know four different numbers: the length, width, average depth, and a multiplier that determines gallons. Here is the formula:

Length * Width * Average Depth * Multiplier = Gallons

Determine the Multiplier:

Rectangle, square, or free-form pond: multiplier = 7.5.

Round or Oval pond: multiplier = 5.9

Determine the Average Depth:

To determine the average depth in a pond where the bottom slopes, measure the shallow end, the deep end depth. Add them together and divide by two (2).

Example: Shallow End = 2'. Deep End = 3'

2' + 3' = 5'; 5'/2 = 2.5' Average Depth


Here's an online calculator that will figure eveything out for you without having to do all the math, it's good whether you live in the USA or UK.

#13 chrisusvi

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Posted 20 September 2009 - 07:17 PM

I was never good at math, but I don't know if it was taken into account that there is a concrete block on both sides. That would minus 16" off total length. Same for the other 2 sides. I just measured it again and the final dimensions are 56" x 32" x 25.5" high. I came up with 178.125 gallons if those numbers are multipled by 7.5.
Am I missing something?
I'm getting flashbacks from high school math class.

#14 koiguy1969

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Posted 20 September 2009 - 07:26 PM

o.k pond demensions are given from inside not out..but at your measurements your pond is 196 gals.
theres definately something fishy about this forum!

#15 koikeepr

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Posted 20 September 2009 - 07:33 PM

that's a pretty small pond. Is there any way you can go bigger? It's not easy to maintain a small body of water like this...I wouldn't go with more than 4 goldies with this pond as is. No good for koi at all.

Can you add to your cement platform to extend even another 3 feet and maybe another foot taller?