startup for ornamental pond

[singingpond]

I have a question related to a small (maybe 3000 gallons? I'm not quite sure) ornamental pond that my mother is having built in her yard. The pond is being built by a pool builder (he is developing a sideline in these garden ponds, and has built a handful of them thus far). The basic construction is a heavy plastic liner, boulders stacked semi-randomly along the sides (looking somewhat like a natural body of water, which is the intent), and then a concrete bottom, with an upper visible layer of white cement and rounded pebbles. I haven't yet seen this bottom layer, but it certainly sounds related to typical pool plaster... or ? There will be a pump, and filter(s) for circulation, water spilling back into the pond over some stacked boulders, but those things have not yet been installed. I believe the intent is to chlorinate this body of water (I've read elsewhere that some garden ponds have an entirely different approach, since people want plants to grow in them, and don't plan to swim in their ponds). Since this particular pond is being built by a pool builder, it is not surprising that he approaches it with pool equipment and pool chemicals in mind.

Now, my main question --

The concrete bottom layer was poured a week ago, and the pond was then partially filled with water (builder told my mom that cement cures better underwater). I was asking her this morning what was being done as far as measurement and maintenance of water chemistry during the past week (I was curious, since I have a vinyl pool, and haven't personally run into plaster curing details before). To my surprise, she said nothing at all has been done over the past week. She assumes, since a PB is building this thing for her, he should know what he is doing. I responded that although her 'pool' is small, I had never heard of total neglect of chemistry as a recommended startup technique!

Am I wrong to be concerned about lack of attention to water chemistry while curing? Is the situation different with such a small volume of water -- maybe the water becomes saturated quickly, and doesn't continue to (potentially) damage the cement?

No chlorine either, yet, in the pond, but there isn't visible algae (yet).

 

[singingpond]

I've had a chance to visit the pond in the meantime, with test kit in hand, of course. My mom was amused by the 'chem lab' at her kitchen sink.

Tap water:
TA 50
CH 50
pH 7.8
No measurable FC or CC

Pond water:
TA 60
CH 70
pH Well above 8.0, added 7 drops of acid demand reagent to get to 7.4
No chlorine

If I look at the acid demand chart in the K2006 booklet, it tells me to add 6.41 oz of full strength muriatic acid to 1000 gallons of water for 7 drops acid demand. If I then set up PoolMath with a 1000 gallon volume and with the measured values for the pond water, set my goal pH to 7.4 and then fiddle with starting pH until it tells me to add approx 6 oz of muriatic acid, I end up with starting pH around 9.9.

I'm pretty sure PoolMath doesn't work accurately at these extremes... However, I think it is correct to conclude that pH (and hence CSI) are quite high in the water at the moment.

What are the main hazards?

The pond bottom is a fairly rough whitish concrete, with pebbles sprinkled in. It doesn't look finished or smooth, as I imagine a typical pool plaster job would. So, from an aesthetic point of view, further roughening of the finish would not be terribly noticeable.

The pond only has about 8" of water in it at the moment, in case that is relevant.

No sign of algae... Perhaps algae doesn't like the high pH?

 

[PoolguyinCT]

Follow the contractors instructions. You don't know if he uses a "proprietary" concrete formula - admixture, watertight or waterproofing, or accelerants. Curing is a chemical reaction in itself.

& btw proprietary concrete formulas are his property & he is under zero obligation to share any formula..

 

[singingpond]

No instructions were given. I doubt there was any high tech special formula involved... They mixed small batches of the stuff in an on-site mixer, dumped it in batch by batch, and sprinkled on the pebbles for decoration.

So far, I guess we are following the (lack of) instructions - we haven't added anything to the water.

In case it wasn't clear, I used PoolMath only to get an approximate idea of current pH, not to plan any actual addition of chemicals.

 

[singingpond]

And if high CSI leads to risk of scaling on the boulders around the pond, that definitely is the customer's business, regardless of any trade secrets pertaining to the concrete mix.

 

[singingpond]

Hmmm... over 100 views, and no responses so far on the chemistry. I'll keep checking in occasionally to see if anyone has any comments.

I did want to clarify something -- the last several posts above seem to suggest an adversarial relationship with the builder, which is not the case at all. The builder is a friend of the family, and his associate, who is doing most of the work on this particular project, is actually a member of our family. However, the person doing most of the work knows very little about pools, and his friend (the PB) who should be guiding that aspect of the project is not on site very often. And, on this forum, we all know that a fair number of PBs don't really know all that much about proper startup anyway.

So, I don't think the lack of attention to chemistry is a carefully planned thing in this case -- more likely something that either fell into the cracks, or was not appreciated by the builder(s) in the first place.

Please help me out, so that I can provide some useful input on this aspect of the pond project!

 

[Serious1]

we have a 3000 gallon pond and we don't use any chemicals nor do I test the water. It has algae blooms in the spring and it's part of the natural state of the pond. We grow water lily's and we have about 17 goldfish (started with 4 and they produced more) 4 large koi, and 2 bullfrogs. The only thing we worry about is the temperature of the water, it gets overly hot in the summer and we sometimes throw a pond heater on it in the winter to keep a small portion of the top open for gases to escape. The pump runs 24/7 365 days a year. That's why it's strange to me that people worry about pool pumps running 24/7 for the summer months. The pond costs $11 a month to run full time.

In the fall we clean the sponge filters on top of the waterfall and we clean out the filter and basket as needed which is normally weekly in the fall due to leaves. It's pretty low maintenance and looks beautiful. The waterfall sound is wonderful. We built it 11 years ago I believe.

 

[singingpond]

That sounds beautiful! Thanks for the description.

This particular pond, however, is still in the early phases of construction, and my questions were about startup chemistry, vis-a-vis standing water over new concrete.

My mom did consider the possibility of having fish, plants, etc. in there in the long run, but decided to go more the 'pool' route for now -- i.e. clear water maintained with chlorination and pretty standard swimming pool equipment. They're even planning to put a skimmer in the darn thing (!) -- that's what comes from having a pool builder going into the garden pond business, I guess.

When I was over there yesterday, I noticed that the pond, even mid-construction and half full of water, is already a captivating thing. We were watching the ripples from the wind. Also, many of the local birds apparently approve of the nice big watering hole my parents are building for them -- a small flock of morning doves came by for a bath and a drink while we watched. Of course, I'm thinking "chlorine!" while watching all those birds visiting!

 

[singingpond]

Morning check in for me... chemistry comments / suggestions, pretty please ??? 150 views now, and nothing yet on that topic.

The main difference I see from regular plaster start up is that the layer of water in this case is quite shallow, since the concrete is only on the bottom of the pond, and can be completely submerged without filling up the whole basin. Maybe that relatively small volume of water reaches some sort of equilibrium with the concrete faster than the large volume in a typical swimming pool? And, if so, is that good or bad for the concrete??

 

[Mr Bruce]

I'm not sure exactly what you are asking, but it sounds like if you use a combination of

Pool School - Start-up New Plaster

and

Pool School - Guide for Seasonal/Temporary Pools

You'll be fine.

For your earlier comment about pool math being off for small volumes, it isn't. But, if you were concerned about overshooting anything you can always add half of what your think, swirl it around with a brush or net, test and adjust as necessary.

 

[singingpond]

I never said PoolMath was off for small volumes. I believe it is off when you get into very high or very low pH values (in other words, the 9.9 pH I came up with in post #2 is probably not very accurate).

My questions are entirely about start up chemistry with new concrete. Long term maintenance is not a concern at the moment.

To recapitulate, my questions are:

1) What are the hazards to the concrete (and perhaps cosmetic hazards to boulders around the pool?), given the current water chemistry?

2) Are those hazards significant enough that we should adjust the chemistry, despite complete lack of instructions from the builder?

3) Is the chemistry different than in a typical pool, since the volume of water over the new concrete is relatively small, and may reach a saturation or equilibrium state?

edited to add: one more question, out of curiosity at lack of algae after a week and a half without chlorine --
4) Does algae dislike high pH?

 

[singingpond]

222 views -- a nice number! Questions remain as above.

I may have a chance to test water in the pond again over the weekend. Builder is reported to have put "some sort of acid" in yesterday to counteract high pH. Still no circulation, but that's rumored to be coming soon. He also added chlorine, in some form.

 

[harleysilo]

I'd be more concerned with lack of a bottom drain than keeping the water on top of the concrete's chemistry correct. If she has considered having fish in that pond, a bottom drain, with the concrete sloped to it, would make it much easier to keep clean, potentially crystal clear clean with the proper amount of filtration. At any rate, if the water starts to turn green and her intention is to have the water clear, i'd add bleach to keep algae at bay so as the concrete doesn't get stained. I'm sure it could be pressure washed back to looking like new as well, but you'd have to drain it and then pump out the dirty water created during the pressure washing.

 

[singingpond]

The pond owner (my mom) has no intention of keeping fish in there (the possibility was discussed before construction began, and the builder did mention that it would have to be built a bit differently to work well for fish).

I'm kind of surprised that no one who responded (so far) seems to see any problem with not following typical pool startup procedure for new concrete -- is that because this particular 'pool' is small, or not a complete pool shell with sides, or... what?

I was over for a visit yesterday, and measured chlorine and pH. Chlorine was back down to zero (not surprising, since it was several days since builder had added some chlorine), and pH was still higher than the top of the scale (however, it was lower than last week, as it took fewer drops of the Taylor acid demand reagent to get down into the correct range). I put some CYA in a sock, in a floater (circulation is still not running). Also put in some chlorine (liquid) -- just enough to get it up to ~1 ppm, as there is no stabilizer in there yet, and it isn't my pool. Not wanting to step on anyone's toes either, as my mom had asked the builder to stop in again today to add acid and chlorine.

After putting in the chlorine, I brushed the bottom to stir things up, and a lot of dust came up from the concrete, which I guess is normal... but made me wish I could vacuum that up and get it out of there.

Plumbing has been connected, and the system had a short test run on improvised wiring -- it was fun to see the waterfall working! However, they are still waiting on an electrician to connect the wires properly, so the setup has basically been without circulation for close to two weeks.

Filtration will be done with cartridge filters, but in an interesting configuration I have not seen before... There are two skimmers installed, each with a cylindrical container down below the skimmer basket (so the container is below ground level) -- that is where the cartridge sits. Pipe then runs underground from those two filter containers, and goes to the pump. Each filter is 50 sq ft, so a total of 100 sq ft, which seems pretty decent for an estimated 5000 gallons of water.

So, if anyone has any comments, I'd be happy to hear them. My main questions are still about the startup chemistry (see list of questions in post #11).



I will try to further explain the need for continuous chlorination (not just a dab now and then) to my parents. My mom seems amenable to learning about testing water herself and adding a bit of bleach on a daily basis. However, with the initial period of neglect, I won't be surprised if algae gets a foothold soon. It already looked a bit dubious to me yesterday, but hopefully that was the dust from the concrete.

I don't know how one would get algae out of all those crevices and spaces between the submerged boulders -- can't really brush there as you can in a conventional pool.

 

[singingpond]

I've looked around online for the skimmer assembly I saw, and it apparently is called a skim filter. The Waterway site describes this as an above-ground pool product. I guess putting it below grade is an unconventional use -- I wonder whether that causes any problems with winterizing, or if it doesn't make any difference.

 

[Patrick_B]

I think no one has responded much on the chemistry because this isn't a pool, and we have no idea what the actual "plaster" was that he used, nor do we care to speculate on that. Honestly, its likely not that big a concern with it being a pond and very different from what we normally respond too. Up front, its likely not going to make much difference what happens in the future to this project that wont be chemically treated/mantained, or even seen for that matter. Proportional to the build cost, perhaps it just isn't reasonable to spend that much time and money for startup on such a project. Take it up with the builder, and stop beating up the forum for not responding with the urgency you expect us to have. Enough of calling out the membership here already. This is a pool forum afterall.

 

[singingpond]

I think no one has responded much on the chemistry because this isn't a pool, and we have no idea what the actual "plaster" was that he used, nor do we care to speculate on that. Honestly, its likely not that big a concern with it being a pond and very different from what we normally respond too. Up front, its likely not going to make much difference what happens in the future to this project that wont be chemically treated/mantained, or even seen for that matter. Proportional to the build cost, perhaps it just isn't reasonable to spend that much time and money for startup on such a project. Take it up with the builder, and stop beating up the forum for not responding with the urgency you expect us to have. Enough of calling out the membership here already. This is a pool forum afterall.

What the heck? I'm not beating anyone up.

This basically WILL be maintained with standard pool chemistry; sorry if that wasn't clear for some reason. The appearance and construction is unconventional, however, and the volume is small (~5000 gallons).

"won't be chemically treated/maintained, or even seen for that matter" ???

Is the problem that I haven't posted any pictures? My last two posts were just an update, in case anyone had comments about equipment or chemistry, or in case anyone might actually be interested in the project, God forbid.

All I can say is, I'm glad I'm not a new poster on this forum, as this sort of response from a moderator would have me looking for the EXIT sign promptly.

 

[singingpond]

I apologize to anyone who may have felt 'beat up' by my request for comments on chemistry. I thought pool chemistry questions, a bit off the beaten path, were what this particular subforum is for. My mistake, perhaps.

I may post a picture of the project, once the waterfall is up and running, in case anyone is interested. My young daughter enjoyed a dip in her grandmother's 'pond' yesterday evening, so hers was the inaugural swim, although more of a float and dunk because of the shallow water. Definitely more scenic than our little pool at home! Other grandkids (and adults) may follow, although it is definitely getting to the end of the swimming season in this part of the country.

Otherwise, I guess I am done with this thread. Thanks to all who replied with helpful suggestions and comments!

 

[Patrick_B]

Three times you pointed out post view count versus repsonses. That gives the strong impression of complaining. Perhaps you'll get more now, but there is no need for you to carry on pointing out how we aren't responding in proportion to our viewing of the thread.

 

[singingpond]

It was meant in a joking way; sorry about the alternative interpretation.