Bare Bottom- HDPE | Starboard | ABS

[BradB]

In my experience, anything inside a reef tank rapidly covers with corraline, and you do get some fine sediment even if you don't add any. The bottom of your tank will look the same in a few months no matter what you use.

Glass breaking may or may not be a legit issue. I've never heard of this, and would think anything supporting 2000lbs of water would not break from a < 100lbs rock dropped < 3 feet through water, and anything that could break it would go right through whatever bottom material you used. I've been told by aquarists that the glass in our tanks can stop a bullet, but I've never tried it.

Right now, I am barebottom with the exception of some fine sediment blowing around - but this is an acrylic tank.

 

[Reefahholic]

Interested to see how long I can go BB before I’m tempted to dump sand in the tank.

At least if I start out with Starboard, I can add or even remove sand as I feel like it.

If you didn’t start with Starboard or ABS, it would be hard to get a sheet under the rocks. Lol you’d have to just accept the glass bottom.

For me, $60 is well worth it in the beginning so that later I can do whatever I like.

 

[SciGuy2]

I've been toying with pouring a cement bottom cover layer in a tank one day. One would have to age it with lots of water changes like DIY agracrete, though. By adding pieces of coral rubble, shells and a dusting of oolitic sand at the top of the pour when it was wet it could be made to have a more interesting texture than a plastic bottom. The cement could be sloped to create "detritus traps" for easy cleaning operations or poured over PVC plumbing to create closed loops in the tank, etc. Just a crazy idea...

 

[AlgaeBarn]

Here’s some more information:

Jul 25, 2017

cilyjrActive MemberR2R Supporter Build Thread Contributor Reef Tank 365
I did some looking into plastics a while back here's what I found (I wrote this for a thead a whike back)...
there are 3 types of food safe plastics commonly available on the market.
1. HDPE (high density polyethylene, recycle code 2) is the most common because of its rigidity. Pretty much all 5 gallon buckets are made of it. it is also what the large brute containers are made from. I use these in the restaurant to store flour sugar ect. and can be bought at any commercial food service suppliers, from home depot, and lowes with caution. it is important to note that NOT ALL HDPE is food safe however. this is because as it is molded, a release agent is sometimes used in the manufacturing to make it easier to remove from the mold. many release agents are toxic.

2. LLDPE or LDPE (linear low density polyethylene, recycle code 4) is less rigid. Most of your rubbermade containers are made from it. We use these in the restaurant to mix and hold things like coleslaw and large batches of orzo salad ect. these can be bought from commercial food service suppliers, home depot, and lowes and have little risk of not being food safe they are however less rigid (think of a bucket you use to put fall leaves into) and may not be the best for long term storage because of the possibility of becoming deformed. I find containers that use this plastic personally as its cheap and easy to find and because of its flexability it doesn't have the same mold release issues HDPE has. but I do worry about them breaking.

3. PP (polypropylene, recycle code 5) it might be hard to find a large container made of PP. it is mostly used in those little brown bottles that your prescription pills came in and the disposable ziploc containers with the blue lids that have taken over your kitchen. the issue with PP is The Environmental Working Group classifies polypropylene as a low to moderate health hazard. they state "two substances found to leach from polypropylene labware - an antimicrobial chemical known as quaternary ammonium and a plastic softening agent called oleamide" this might be only because PP is used in some makeup as an ingredient.

the other plastics i would not use though they are in many bottles one finds food in is PETE (polyethylene terephthalate recycle code 1) as it is known to leach BPA over long periods. and OTHER (other recycle code 7) this really speaks for it self. it is anything that does not fit in the other categories. it could be ok but you cannot know.

finally vinyl (PVC recycle code 3) strangely not considered food safe due to the use of phthalates to soften the plastic. many companies are using non-phthalate plasticizers since 2010 so it may be changed at some point.

thats what I found. my curiosity was piqued for both the hobby and my work (a few years ago when the #7 plastic ban happened due to bpa) anyway thats what i found i hope it helps

I would be kind of amazed if high quality HDPE was a chief cause of those peoples tank crashing. Its really chemically resistant. We could always do UHMW-PE, but its hard to keep that stuff from bowing and it ain't cheap. I'd be more concerned about dead zones underneath the plastic bottom flowing back into the tank (nice anoxic zone) causing tank disruptions than quality plastic.

We do have to wonder if PVC is potentially leaching phthalates and therefore we dont want to have a PVC bottom, then why do we use PVC piping . I'm pretty sure the most common phthalate for PVC was Santicizer S160, Benzyl butyl phthalate, back in the day (known endocrine disrupter) . It has amazing properties for making plastics more flexible and less brittle, but they have started making a lot of different "Green" plasticizers instead of phthalates.

I think this might be a case of over analyzing. If you lookup plastic leaching for endocrine disrupters (which is one of the main effects of phthalates), you will find a variety of results. One paper even says that unstressed acrylic will leach (and who is going to blame their acrylic tank for causing their aquarium to crash).

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4063249/



Overall, the most literature I could find was showing HDPE was one of the best materials to use (based on saline extraction of compounds with endocrine activity).

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3222987/


I would imagine PETG (PET + Glycol modified) would also work.

 

[Reefahholic]

Interesting guys. The concrete idea is similar to an idea I had with reef flakes sand.

I thought about using a silicone spread all over the Starboard and than sprinkling sand over it. You could use a piece of plywood on top to gently press the sand into the silicone and then remove it and let the silicone dry with the top layer of sand on/in it. Would not blow around and would look better than a bare bottom.


Those papers are interesting. I doubt the HDPE crashed the tanks, but I find it strange how one is recommended for interior use and the other (Starboard) is Marine Grade for exterior use. Yet they are supposed to be the same HDPE material.

Maybe somebody can clarify this for us.

 

[AlgaeBarn]

Interesting guys. The concrete idea is similar to an idea I had with reef flakes sand.

I thought about using a silicone spread all over the Starboard and than sprinkling sand over it. You could use a piece of plywood on top to gently press the sand into the silicone and then remove it and let the silicone dry with the top layer of sand on/in it. Would not blow around and would look better than a bare bottom.


Those papers are interesting. I doubt the HDPE crashed the tanks, but I find it strange how one is recommended for interior use and the other (Starboard) is Marine Grade for exterior use. Yet they are supposed to be the same HDPE material.

Maybe somebody can clarify this for us.

Outdoor grade plastics tend to contain UV absorbents/inhibitors to quench any free radicals generated through UV radiation.

 

[Reefahholic]

Outdoor grade plastics tend to contain UV absorbents/inhibitors to quench any free radicals generated through UV radiation.

So it’s basically the same exact thing. Just UV protected. That’s what tap plastics told me when I called.

So just that one thing is why they’re calling it interior vs exterior?

Remember, they say Starboard is 20-25% heavier than regular HDPE. So there’s gotta be more to it than the UV protection.

I need to call a few companies again.

 

[AlgaeBarn]

So it’s basically the same exact thing. Just UV protected. That’s what tap plastics told me when I called.

So just that one thing is why they’re calling it interior vs exterior?

Remember, they say Starboard is 20-25% heavier than regular HDPE. So there’s gotta be more to it than the UV protection.

I need to call a few companies again.

That tends to be the difference between interior vs exterior plastics (uv inhibitors)

I'm going to call BS on the 20-25% heavier (not sure where this is mentioned). I have starboards spec sheet here:

https://www.interstateplastics.com/docs/interstate-plastics-king-starboard-specs-uses.pdf

This is right inline with standard HDPE (1.4% higher than the minimal density).

I guess one of the nicer things about starboard is their UV inhibitors are food grade.

 

[Mebeknob]

Starting up a new bare bottom tank myself and I wanted to go with frag tiles. that way once corals grow I can remove the tile, frag it and then just replace with a new tile.

could tiles be added into this equation? or is there a negative side i'm overlooking?

I tried this approach with just normal square tiles. I got tons of detritus.
You might have better luck if you have CNC cut squares so there is no space for crap to find it’s way down.

 

[Reefahholic]

I'm going to call crap on the 20-25% heavier (not sure where this is mentioned).

It was mentioned in a video I believe. I'll try to find it.

 

[Reefahholic]

OK, I checked the Density on Starboard vs HDPE from a few websites on their spec sheets and they all read the same at 0.955 g/cc for both materials. So it looks like the only difference with Starboard vs HDPE is the UV protection. They do have an antimicrobial technology called "MicroShield" for protecting the product surface against stain and odor causing bacteria, algae and fungi, but this is an upgrade and doesn't come standard.

Both the regular King HDPE and Starboard are produced with K-Stran, the most advanced manufacturing process for superior flatness and consistency. So they should both hold up about the same in our reef tanks.

Regarding the 20-25% heavier comment. I couldn't find anything in the videos. I believe the guy I talked to from Tap Plastics was referring to the XL. King StarBoard XL is a lighter version of the King StarBoard. King StarBoard XL sheets are up to 30% lighter in weight than King StarBoard. The HDPE appears to weigh exactly the same as Starboard.

So the only real difference with HDPE vs Starboard (that I can see) is the UV protection / "environmentally stabilized" part.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


***King StarBoard® is the original marine-grade polymer sheet and the industry standard. It is the product of a proprietary process called K-Stran™, the most advanced manufacturing process for superior flatness and consistency. King StarBoard® is environmentally stabilized to withstand the harshest marine conditions. It will not warp, rot, or delaminate when exposed to humidity or water. King StarBoard® is easy to fabricate with standard woodworking tools and requires little or no finishing. King StarBoard® is upgradable to King MicroShield® with an advanced antimicrobial technology for protecting the product surface against stain and odor causing bacteria, algae and fungi.***


***King KPC high-density polyethylene (HDPE) is produced with our proprietary K-Stran™ process for unsurpassed flatness and quality up to 1-1/2” in thickness. For larger gauges, our state-of-the-art compression molding system is utilized to create the same quality sheets, slabs and massive shapes. King KPC HDPE natural is FDA, USDA and FPA approved material that can be used for food containers and food equipment.* It is extremely versatile with outstanding properties and good chemical resistance for a wide variety of applications at a very competitive cost. King KPC HDPE has a low coefficient of friction and can be easily cut, machined, welded, and thermoformed for easy fabrication. It may be used for some structural fabrication because of its superior tensile strength. It is moisture resistant, impact resistant and has great abrasion resistance. The material will not splinter or rot; resists stain and odor causing bacteria; and is very resistant to cleaning agents. For best cleaning results refer to Chemical Resistance Chart.***

 

[Mebeknob]

It probably won't be a big issue unless you do the tiles.
The HDPE will float. Or it will at least be neutrally buoyant in the water based on densities.
(This is why I chose HDPE for my underwater rover frame because then I can stop power to the motors and it will basically stay in the same place)
SO just keep that in mind if you're not going to have anything on top of it to keep it down.

 

[Reefahholic]

It probably won't be a big issue unless you do the tiles.
The HDPE will float. Or it will at least be neutrally buoyant in the water based on densities.
(This is why I chose HDPE for my underwater rover frame because then I can stop power to the motors and it will basically stay in the same place)
SO just keep that in mind if you're not going to have anything on top of it to keep it down.

I think most people plan to put rock and coral on top of it.

 

[Mebeknob]

I think most people plan to put rock and coral on top of it.

Like I said, it won't be an issue unless he does the squares for frag plugs. It that situation he might not have frags on all the pieces.

But if he did a cool CNC pattern to cut all the frag pieces that could lock together somehow...

 

[SciGuy2]

If a person can't figure out a way to keep an HDPE bottom plate on the aquarium bottom they won't be reef keeping very long.

 

[showmebutterfly]

Not reef safe since it says it resists mold and mildew and UV-resistant? I like the price, so I figure it's probably not reef safe.

https://www.menards.com/main/doors-...730-c-7551.htm?tid=2826338291244692847&ipos=1

 

[Mebeknob]

If a person can't figure out a way to keep an HDPE bottom plate on the aquarium bottom they won't be reef keeping very long.

Now how about 100 little floating frag plates? Lol

 

[Reefahholic]

Not reef safe since it says it resists mold and mildew and UV-resistant? I like the price, so I figure it's probably not reef safe.

https://www.menards.com/main/doors-...730-c-7551.htm?tid=2826338291244692847&ipos=1

No, HDPE and Starboard are Reef safe. They’re FDA and USDA approved.

 

[Reefahholic]

Not reef safe since it says it resists mold and mildew and UV-resistant? I like the price, so I figure it's probably not reef safe.

https://www.menards.com/main/doors-...730-c-7551.htm?tid=2826338291244692847&ipos=1

I have it pre cut at Tap plastics or Eplastics.

 

[showmebutterfly]

Woo-hoo! Thanks for the info. [emoji3]

No, HDPE and Starboard are Reef safe. They’re FDA and USDA approved.