3 Pack Waterfall Foam Sealant Black Spray for Ponds & Rock Gaps 16oz Each

   
• Direct the beauty of flowing water exactly where you want it! Half Off Pond's black expanding foam helps seal gaps between waterfall rocks and streambeds, ensuring water flows over—not under—your landscape features. Ideal for dramatic visuals in koi ponds and pondless waterfalls.
   
• Designed to support heavy rocks and stones, this waterproof foam sealant provides reliable adhesion and structural reinforcement. Perfect for use in pond foam applications, waterfall foam sealant work, and rock glue setups outdoors.
   
• Whether you're a seasoned pro or weekend warrior, this 3 pack spray foam gap filler is easy to apply with the attached straw nozzle. Preferred by contractors for large pond and commercial installations, and simple enough for home use.
   
• Formulated with high-performance black polyurethane spray foam, it resists UV damage and remains flexible once cured. Expanding foam sealant stays strong in wet environments, making it ideal for landscape foam and outdoor water features.
   
• Each can dispenses easily with a built-in straw, giving you precision control on the job. Whether you’re using it as pond foam sealant or gap filler for waterfall foam applications, it’s the go-to solution for fast, effective results.

FAQs & Calculations to Help Select the Correct Kit

Rectangular Ponds

Length x Width x Average Depth x 7.48 = Gallons

Example: A rectangular pond 15’ long, 10’ wide and 1.5’ Deep Pond is...

15’ x 10’ x 1.5’ x 7.48 = 1683 Gallons

Oval Ponds

Length x Width x Average Depth x 0.8 x 7.48 = Gallons

Example: An oval pond 15’ long, 10’ wide and 1.5’ deep is...

15’ x 10’ x 1.5’ x 7.48 = 1683 Gallons

Round Ponds

Length x Width x Average Depth x 7.48 =Gallons

Example: 15’ long, 10’ wide and 1.5’ Deep Pond

15’ x 10’ x 1.5’ x 7.48 = 1683 Gallons

 

Streams

Length x Width x Average Depth x 0.25 x 7.48 = GALLONS =Gallons

Example: 15’ long, 10’ wide and 1.5’ Deep Pond

15’ x 10’ x 1.5’ x 7.48 = 1683 Gallons

 

2. How Big of a Pump Do I Need??

Minimum pump size is determined by pond type, water volume, head height and friction loss. The minimum pump size recommendations are:

Water Garden, Few Small Goldfish

Circulate total pond water valoume every 2 hours.

Example: 2,000 GPH pump for a 3000-gallon pond with 2’ waterfall.

Fish Pond, Several Small Fish

Circulate total pond water valoume every 1 hour.

Example: 3,800 GPH pump for a 3000-gallon pond with 2’ waterfall.

 

Koi Pond, Several Large Fish

Circulate total pond water valoume every 3/4 hours.

Example: 2,000 GPH pump for a 3000-gallon pond with 2’ waterfall.

Calculating Head Height

Dynamic head pressure is found by taking the vertical height of your waterfall; the distance between where your pump is (typically in the skimmer) and where your waterfall is, and adding the static head pressure (pipe and fittings) 1’ for every 10’ of tubing and 1’ for every elbow or “T” fitting.

Example: 3' (vertical height) + 2.5 (25' of tubing) + 2' (for 2 elbows) = 7.5' of Dynamic Head Pressure

Note:It is important to take into consideration while calculating how much flow will be at the top of your waterfall by accounting for the head height due to the laws of fluid dynamics. Please refer to the flow chart above to help choose the correct pump.

 

3. What Size Tubing Do I Need?

Tubing Size	Efficiency GPH	Minimum GPH	Maximum GPH
0.5”	< 300	60	420
0.75”	< 720	300	900
1”	< 1,200	700	1,500
1.25”	< 1,600	900	3,200
1.5”	< 2,600	2,000	4,400
2”	< 4,800	3,000	6,800
3”	< 9,000	6,000	14,000
4”	< 21,000	14,000	28,000
6”	< 42,000	33,000	60,000

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About Half Off Ponds

Customer service is our business. We have been satisfying fish pond, water garden, and backyard waterfall enthusiasts for over 25 years! We're glad to assist you with your pond building project - from start, to finish!

Thanks for your business! We appreciate it!

- The Half Off Ponds Team