JDHOGG Posted March 20, 2004 Share Posted March 20, 2004 Seems like everybody is looking for a source of good rock for their tanks. What is the stuff for sale at the LFS to expensive? Yeh well it is for me. I know of a place where their is millons of basalt (I think) boulders of varying sizes. The rocks are a dark grey shading to lighter grey. They are smooth to touch but are pitted in many places. The trouble is they are from a rocky beach down past Albion park (Past Wollongong) near Bombo. I don't know if it is really ethical (or legal)taking these rocks of the beach but their really is gazillions of them and a lot of locals have them all in their gardens so they seem to take it. The trouble is they are really heavy. More than twice as heavy as similar sized sandstone. Are rocks taken from the ocean likely to be cleaner than rocks taken from elswhere? Also has any one tried making rocks from cement covered polystyrene? I have seen a few internet sites talking about this and I was wondering if any one has tried it and how they went. I am a bit paroniod about putting heavy rocks in my tank and this sounds like a good alternative. Does anyone put anything under the rocks in their tanks to protect the glass? If so what do you use? I really like the look of large rocks in a tank but like I said I am worried about breaking the glass. regards, JDHOGG 5. Please do not SHOUT (i.e.: using ALL CAPS). Link to comment Share on other sites More sharing options...
Sarah Posted March 20, 2004 Share Posted March 20, 2004 JDHOGG some people place a sheet of styrofoam on the bottom , and then the rocks followed by the substrate cheers Link to comment Share on other sites More sharing options...
Colfish Posted March 21, 2004 Share Posted March 21, 2004 hi jdh as you i also like to have rocks, they give a more natural look to the tank, but are a real pain in breeding tanks. the price of rocks at lfs is high, just general loose rocks go for $6 $10 kg, larger peices & feature rocks, yeh how bad do you want them. when you consider it $500 is not over the top to do a 6x2. but i suppose you must think of the work involved with collecting & transporting, although it is rock it does break & a large feature rock can easily be reduced to rubble. however, try making you own! [sorry no links to any sites] just my own diy method. use a thick bed of sand [on the ground- where ever] spread out relative to the size of rock required. make a reverse pattern of lumps & bumps & caves [don't try to outdo michaelangelo] make up required amount of premix concrete to a fairly dry mix & place into the mould, don't 'play' with finish, you want it rough. when dry leave it in sun for a day or two then put it in a shallow tub to cure change the water once a week let the algae grow & in a short time you won't pick it from the real mc-coy. sounds involved but really easy make 2or3 at a time & in no time you'll have a rock pile. regards colfish. Link to comment Share on other sites More sharing options...
JDHOGG Posted March 21, 2004 Author Share Posted March 21, 2004 Thanks Colfish. So are you saying that you have DIY imitation rocks made out of solid concrete? Sounds cool. I am getting a 6x2frt soon and yeh like you said it will cost a lot to rock it up. So thats why I am looking at alternatives. I am looking at getting a tropheus colony and so I was going to try and have rocks that are tall and placed irregularly so that they break up the line of site from one end of the tank to the other. My theory is that the fish that are being chased can duck and weave around the rock pillars and escape the aggressor. How large were the rocks you made? thanks, jdhogg Link to comment Share on other sites More sharing options...
anchar Posted March 21, 2004 Share Posted March 21, 2004 I have coated polystyrene (model grade is denser and better) with cement to great effect. You can colour the cement with mortar colours or supermarket dies, or sprinkle sand into the drying cement. You will need to wash/soak it when it's dry to remove excess lime which will otherwise adversely affect your pH. These rocks are not suitable in soft-water setups. The advantage of using styrene as a base is the lighter weight achieved using this method. merjo Link to comment Share on other sites More sharing options...
JDHOGG Posted March 21, 2004 Author Share Posted March 21, 2004 Thanks Merjo. I was thinking of trying this but don't the rocks float? I read that some people silicone them to the back of the tank, but I want to be able to move them around. Or do you coat them with heaps of cement until it's heavy enough to sink. Where do you get the "model grade" polystyrene from? regards, jdhogg Link to comment Share on other sites More sharing options...
Colfish Posted March 21, 2004 Share Posted March 21, 2004 hi jdh yes i do use these rocks. sure they are made of conrete, but as i said keep the mix fairly dry, and don't pat,play or otherways with it. this leaves the mix fairly open therefore reducing the weight. i have made a variety of sizes and shapes anything that will fit in the tank and you can lift. marine live rock is too exspensive to build up a large base with, i've used these rocks for that purpose also[really holds the Ca, ph and gh/kh well], anyhow give it a trial run and see how you go.cheers;colfish Link to comment Share on other sites More sharing options...
anchar Posted March 21, 2004 Share Posted March 21, 2004 Yes they will float so they need to be anchored with silicone to the base of the tank. Obviously your aquarium will need to be empty and dry when applying the adhesive. merjo PS I have usually anchored them in place, given at least a week to cure, then filled and emptied the tank a number of times. This will flush most of the excess lime away before setting it up for fish. Link to comment Share on other sites More sharing options...
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