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Aquatic Gardens

Ponds, Streams, Waterfalls & Fountains:
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples

V. 1 Print and eBook on Amazon
V. 2 Print and eBook on Amazon

by Robert (Bob) Fenner

pond mortar     6/13/17
From searching your posts I have found the following two recipes for waterproof concrete and mortar. Can you please help me decide which is best to use. I am building a small pond to hold 400-550 gallons of water. I will be using extremely large river boulders as large as a washing machine to frame to pond. I will be setting down a liner with stucco wire/concrete mesh/chicken wire like you described. I want to build as I go, having the pond be primarily built from large river rock (basketball sized to softball sized).
Question 1: Which concrete recipe or mortar recipe should I use?
Recipe 1:
3 Aggregate (1/4 pea gravel)
2 Sand (sharp)
1 Cement (plastic cement)

Recipe 2:
4 Aggregate (1/4 pea gravel)
2 Sand (sharp)
1 Cement (plastic cement)
<I'd go with recipe #1, less aggregate... Three parts here will be enough>

Question 2: Is there a foundation coating, cure retardant or additive I should use that will not change the color too much of the natural stone (clear coating is ok, shiny is ok, white is not ok).
<Mmm; no coating... mask off (paper or trash bags, tape) and try to not get too much cement/concrete on the rocks... sponge (large yellow ones at the concrete place) what you can while it's still wet... read on WWM, elsewhere re acid washing to remove the rest after all is set>
Question 3: There is not a home depot or Lowes around me that sells “plastic cement”, I live at 10,000 feet in Colorado. Can I make my own “plastic cement” somehow?
<Mmm, well; you can/could add plasticizing materials (such as limestone, hydrated or hydraulic lime); be careful with the last two (wear a breathing mask, gloves) as they're very alkaline...>

Question 4: There is one concrete producer an hour away that sells a “shotcrete” mix with the option of an additive mesh of some sort…would this work?
<Yes... but this term refers only to the fact that the blend is intended to be applied by high pressure...>
Thank you,
<All these types/kinds of concrete will work for you here. I suggest putting the liner and wire down... having friends over to help mix and apply whatever you end up with. Take your time. Bob Fenner>
Re: pond mortar     6/13/17

Wow! Thank you! I looked to see if just hydrated or hydraulic lime was available and no, it’s not. I have only used pre-mixed mortar in the past but I want to use your recipes and advise.
Question 1: Would this mix below work for the rock work I explained or should I add more less of something?
<Let's see...>
5 gallons of water (give or take)
18 shovels of aggregate/sand (I have sand from an old river mining operation. It is bank run dirt, washed and classified to half an inch, therefore everything in the sand is half inch and smaller) Would this count as my sand and aggregate both or just sand?
<Better to have sand AND aggregate... and for such a small pond/basin, "pea gravel", nominal 1/4" diameter. Half is really getting to be too big. IF you can, you want to keep the wall thickness down to 3-4"... easier to do w/ smaller grade gravel. The mix ingredients are overall okay... again, see y/our prev. email for relative volumes. 3:2:1, and just enough water for slump>
Another option is that I buy pea gravel and crush some rocks in a rock crusher (I have plenty of large rocks to crush)
<Yes... or likely easier (what I would do), sieve out the too-large bits, use them elsewhere (as in a mix for falls...)>
<And you, Bob Fenner>

Leaking pond made of concrete sections   4/29/10
Our 9' diameter pond was constructed of 6 concrete sidewall sections, all of which are cemented together and on top of a concrete deck (base). To stop leakage at the concrete-grouted seams where the sections abut each other and between the sections and the concrete base, I have successfully used Marine GOOP, a clear and goopy sealer
applied from a tube and smeared over the leaking surfaces.
<Am familiar... is "amazing">
After 10 years of mostly leak free operation, the pond is now leaking rapidly and re-application of GOOP has not solved the problem. I have removed the newly applied GOOP using acetone but have not yet applied it a second time. The seams are flush with the side sections and can't easily be caulked. The side sections are made to look old and are impregnated with a color stain. Using a liner or applying an overall coating is not acceptable. Do you have any other suggestions for sealing the seams?
<Mmm... there may be a elastomeric product that will work here... The seams will have to be meticulously clean and dry... I'll plug my fave line: Thoro: http://www.thoroproducts.com/
and read here re use:
and the linked files above. Bob Fenner>
Re: Leaking pond made of concrete sections
Thanks for the information.
<Welcome. BobF, who's been there, done this...>

Pond Liner I'm just starting my outdoor pond.  The pond is built on cement floor and surrounded by cinder block wall as an extension of my planters.  What adhesive can I use to adhere the liner to the cinder block walls? <Mmm... would be best to "capture" the loose edge under a cap if still possible... mortared over the edge with plastic cement, thin-set and Acrylmix... If you can't do this, please write back and we'll talk. BobF, leaving Houston>

Will blocks cut the pond liner  5/29/06 Bob, We are building a pond using blocks.  The pond is 15 x 25.  Will the top of the blocks cut the liner over time? We will be using 42 mil liner then "topping" it with flag stone.  Thanks. <You should be fine here... this sort and thickness of liner is VERY tough... I would first lay-in the liner (w/o mortar), fill the pond, place the flagstone... allow all to sit for a few days... see if this is about what you're looking for... remove the flagstone, trim the liner where it is overlapping over the outside of the flagstone... and re-place, mortar it in place... with or without reinforcing mesh (Leaving the cap non-mortared is too likely to lead to pieces falling in, this potentially puncturing the liner. Bob Fenner>

Cinder Block And Plaster Pond   4/7/06 Hi Robert, <Renel> We in the midst of building a four foot deep cinder block  pond...two feet in ground and two feet above ground.  It is eight feet wide  and twelve feet long.  We poured the foundation with a bottom  drain, set the cinder blocks, and drilled the holes in the cinder blocks  for the returns to jets and skimmer. Now we are back filling the outside  wall and getting ready to brown coat the interior and exterior walls.  At  this time we are also setting up the plumbing system.  Next comes the  pebble finish... my neighbor has a pool plastering business and has  volunteered to do this as a favor.  My question is, what next? How do  I make the pond water safe for my Koi after the plastering/pebble finish? <Mmm, please stop at the brown coating step... And make sure, absolutely sure that the basin is water proof. I would do a bit more here to assure this... perhaps a "between slab" waterproofing (there are a few approaches here), or at least a water proofing cementaceous coating... At any length, do take the time (a week or more) to fill this pond up... fire the mechanicals over to also check re, and leave the basin filled (before back-filling if possible) and measure water depth daily... ahead of applying the (expensive) pebble coating on the inside. The epoxy, materials used in the pebble-coat are actually not hard to cure for biological use... can be lightly bleach/acid-washed per the manufacturer (a protocol is detailed on WWM), and am very sure your neighbor/installer will know of this. After filling, rinsing, re-filling, best to let the system operate a good while (month) or more, seed with beneficial microbes (from live plants, old fish-pond water, old/used filter media... also detailed on WWM for Establishing Cycling) to assure the system is ready for Koi. Bob Fenner> Please help. Thank you. Renel

Concrete block pond construction I have read with great interest (and thanks) your section on building a pond with concrete block. The walls will be concrete block and I am going to use an EPDM liner. How does one attach the liner to the block under the coping? <Basically, liner is underlain twixt the topmost course of block and whatever you're using as a cap (likely more cementations material or rock, mortared in place. A good technique is to slowly fill the pond without this cap, pulling the liner in place to flatten out, leaving it almost all the way filled to assure a good fit while applying the cap. Bob Fenner>

Block Pond Bob, <John> I am constructing a small (4'x3'x2'), above ground, block pond on top of my concrete patio.  I read in an English pond book that I should coat all interior surfaces with mortar containing fiberglass so that it would stay flexible and be less prone to cracks as time goes by.  They then recommend a final coating with a black tar like substance. <Mmm, well, there are a few materials that might/can be used for such water-proofing. I am NOT a fan of those involving fiberglass... they're neither flexible, nor generally long-lasting... and toxic to apply and can be problematical when they ultimately delaminate... Short answer, I would use another technique> I can not identify the fiberglass mortar here in the states and am not sure exactly what the black stuff would be. <The fiberglass is likely one of two possibilities, one is a "forti-fiber" that is added to a mortar slurry to give it strength and substance in application, the lesser probability is a chopped or cloth material added with resin> Today I discovered your web site (fantastic, as you already must know) and saw your recommendation for plastic cement as mortar with a preference for plastic lining even with my above ground block construction. <Yes... If the patio is "stable" (cured/old, substantial... no broken bits/cracks...) and strong enough to handle the weight of the structure and water (should be for what you state), the plastic cement mortar (with a coloring agent if you wish) should "do it". This is the route I would go. Bob Fenner>

Pond construction question      How Do I finish a Block contracted fountain / pond   2.5  block high Depth / 20 inches high. What finish should I use on it ?  8' x 2' is the size of the pond. very small.      Front yard fountain / pond / aquatic plant garden. Please help ? I did read on your site about sealers which should finish off the inside just fine. What would you Suggest ? <A few possibilities for sure... you could apply a scratch coat and then stucco the outside... with or w/o materials that would change the roughness, and with whatever artistic touches in using the hand tools in finishing... I encourage you to visit your local hardware store(s) and ask them what they have available however... it might even be that you'll settle on a course or two of tile or other decorative appliqué in addition to a coating for the outside. Bear in mind that about all such materials can be colored to match your plan, other elements about. Bob Fenner>                                                                                            Morgan

Block and other construction methods for basement shark system Hello Bob, I was thinking about building a block pond in my basement i just have a few questions about it. If its already on a concrete base in my basement do i need any thing under it or do i just need to make sure that its all even? <It is very likely even (planar) enough... and strong> Do I need a liner inside or no I'm not really sure because i cant get this part of your site to open but i have crappy internet service. <Please tell which "part" (name of file) this is... so I can check to see if there is a difficulty on this end)> Well the size pond i am planning is only going to be 7 ft by 7ft on each side and only 3 ft deep. <Three feet... not likely all the way of water... maybe more like up to thirty inches in water depth. If your ground doesn't shake much (unlike ours here in Southern California) you can get by w/o a liner.> Do you think this filtration would work a 75 gallon sump and a euro reef protein skimmer plus some other pumps and power heads inside for more circulation. The only fish i want are 2 cat sharks probably 1 epaulette and 1 coral cat shark also would a port Jackson shark work with these smaller ones or would they be eaten. <Could all be housed together... given being about the same size... and stipulated the Port Jackson was a tropical species (not the Southern California Heterodontus francisci... a cool/coldwater animal). There is a need for good biological and mechanical filtration with these animals... And you might want to instead (if you can get it down there in the basement) a possibility of buying a gel-coated fiberglass tank of size (that you could retrofit a viewing panel, or buy one with... or even assemble a wood, fiberglass and resin tank of about this size (I'd size it to fit back out an opening to the basement...) instead of block and mortar.> Then i would just have one adult Angel fish and 3 or 4 other misc. fish that wouldn't be no bigger than a foot or a foot and a half? Last Question is my porcupine puffer has been having problems eating he looks hungry and even goes forward trying to bite the food but cant get his mouth on it just cant really tell because he is only around 2-3 inches.  <Please read through the puffer FAQs pages on our WetWebMedia.com site here. This is a serious condition that is quite common.> Sorry for so many questions but there's a lot of info i cant find Thanks for all the help you have given me in the past. <Be chatting, planning and building my friend. Bob Fenner>

Aquatic Gardens

Ponds, Streams, Waterfalls & Fountains:
Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples

V. 1 Print and eBook on Amazon
V. 2 Print and eBook on Amazon

by Robert (Bob) Fenner
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