# Is crushed coral ok for substrate?



## RapidSixGuns

hello,

I have a 100gal. with crushed coral substrate. It has crushed coral because I originally wanted to put african cichlids in it. I realize that a bio-substrate is preferred but unfortunately I already have the crushed coral. The cost of replacing the substrate is a bit out of my budget now. The tank has been running for about a month with 3 fish in it (they'll be taken out) to build the bio-nutrients. I think I'm ready to put plants in it but wanted thoughts on whether this substrate will sustain plants like crypts, anubias, and other flora often used by aquarist on this site. No doubt this will not be the ideal biotope for the plants I seek but I just want to know if I'm sending these plants to their immanent death or will they adapt? Bear with me folks as I'm new to all of this. I appreciate any thoughts on this and will take all responses seriously. 

Thanks,
RapidSixGuns (aka. Michael)


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## geeks_15

I would just wait, get the appropriate substrate, and then start planting. Whenever I have tried to set up an aquarium on the cheap with components that I knew were not ideal I have regretted it.

That said, you will probably get some anubias to grow. Some crypts may survive. If the crushed coral makes the water very hard with a very high pH (as preferred by cichlids from the african rift lakes) it will limit the types of plants that will live. A period of trial and error may be necessary to see what will work for you.

For a cheap substrate get a bag of top soil (no fertilizers or chemical additives) from Lowes or Walmart and make a 1 to 3" bottom layer. Then cover the soil with 2" of small gravel substrate (I just got 50 pounds of used substrate at an aquarium club swap meet for $5). Check craigslist for aquarium stuff and before long you'll be able to find some cheap used gravel substrate. Maybe you could even trade your crushed coral for substrate that would work better for a planted tank.


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## Diana K

Crushed coral is fine for a hard water tank. It is heavy enough to hold the roots down, but has very little CEC. It will make the tank water harder, higher pH. This is fine for plants, not so good for soft water fish. 

Look into Rainbow fish, livebearers, Rift Lake fish (not just the aggressive Mbuna sort of set up) and others. 

I have one tank that is about 50% coral sand, and 50% Turface, and even this tank has hard water. Usually Turface removes the KH and drops the pH, but not blended with the crushed coral!


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## RapidSixGuns

Thanks for the advice diana k and geeks 15. I would love to change the substrate but right now I just can't afford to. I figure it would cost at least $100 to change the substrate. A quick update, I did some water testing today (which I don't normally do but should do regularly) and the pH was 7.6-ish, no nitrate, nitrate, and ammonia levels (parts pert million) recorded. Unfortunately, I don't have a hardness or alkalinity test kit yet. I also did a little research on anubias, rotala, and java ferns and found that they may be suitable for this tank. I have 1 anubias coffeefolia and 2 rotala stem bunches and 5 java ferns tied (but not achored yet) on volcanic rock which I put into the tank today. These plants can easily be removed if necessary. The tank is still bear of fish but is still circulating the nutrients from when fish were in it. I'll feed (with iron supplement) today and see where it takes me. This tank was primarily set-up to house Hap. livingstoni's which are still in another tank.

By-the-way, what does "CEC" mean? Also, is turface some kind of substrate additive?

Thanks again,
RapidSixGuns (aka. Michael)


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## geeks_15

With that pH the water is probably not extremely hard and many plants should do fine if that is the case. Growing anubias and java fern can be done with the most basic setup (low light, no fertilizers, any substrate). Just don't bury the rhizome in the substrate or it will rot. Growing stem plants will often require more light, ferts, etc., but not all stem plants will have this requirement.


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## ddavila06

hey Mike, i purchased substrate for my tank from this website: petsolutions.com, they had a great deal then, like 18 bucks per bag of eco complete and the shipping is not by weight, check it out!


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## RapidSixGuns

Thanks for info. and positive assurance geeks 15. Hey Damain, I'll check out that website...I really can't afford a arm nor a leg at this time but if only the sacrifice of a few fingers are needed, hmmm. 

Thanks again folks,
RapidSixGuns (aka. Michael)


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## RapidSixGuns

Thanks Damian for the heads up on petsolutions.com. I went to the site as you had suggested and saw the eco complete substrate. I think it ran for $23 for 20lb bag. I would need about 5 bags to put a good layer down in my 100gal. tank and possible a 6th bag. I think I payed around the same price for the bio-substrate thats in my smaller tanks which I purchased at Petco. Anyways, sometimes you just have to use what you got and be happy you have that much. Perhaps in the spring or early summer I will be able to swap out substrates and when I do I defintely will use a more appropriate substrate for keeping a larger variety of aquatic plants. As always, it's nice to hear from you Damian and we'll defintely keep in touch.

See ya around,
RapidSixGuns (aka. Michael)


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## geeks_15

Use a base of topsoil and cover it with the eco complete. You'll save lots of money and get a more nutrient rich and long lasting substrate (IMHO).


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## RapidSixGuns

Hi folks,

I want to thank everyone for their input. It really gave me a lot to think about. I realize I sort of got off on the wrong foot with my selection of substrate but that was what I had on hand. No doubt crushed coral isn't the ideal substrate but surely it has it's uses in growing aquatic plants. Please continue to give feedback and tips as I read all of this and find some way to take what I can use and leave the rest behind. 

Also, this thread is currently running in the substrate forum (probably where it belongs in the 1st place) so please enter any further responses in that thread. It's hard to keep up with 2 threads of the same topic.

When I figure out how to insert pic.'s I will display where I am currently at on this tank.

Much thanks to all that helped,
RapidSixGuns (aka. Michael)


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## 90gal

You'll hear a lot of folks saying you need massive $$$$ for a planted tank. You CAN take it one step at a time; I started with inert (no real value to the plants) substrate that I bought at a bulk landscape place - $5 per bag of gravel; as much as you could fit in the bag. Needless to say, I got two bags which weighed AT LEAST 50 pounds each. It was inert; but you can always use plant tabs later on if needed. Plus; I had a HORRIBLE time with "mineralized substrate" seeping through the cap of substrate and it's a headache with a larger tank. Shoot me a PM and we'll chat if you'd like...


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## RapidSixGuns

PM sent


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## AaronT

Crushed coral is an inappropriate freshwater planted substrate. It might grow some hard water loving plants well, but your selection will be severely limited. You'd do well to get a plant specific substrate or even just an inert gravel to start with. Why start with a handicap from the beginning?


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## ddavila06

AaronT said:


> Crushed coral is an inappropriate freshwater planted substrate. It might grow some hard water loving plants well, but your selection will be severely limited. You'd do well to get a plant specific substrate or even just an inert gravel to start with. Why start with a handicap from the beginning?


Hey Aaron, since he wanted to keep his africans and at the same time have plants maybe we can suggest some hard water-high ph resistan plants? i don't know much on that subject, but i think anubias and ferns will do well, that if attached to rocks and/or wood, right?


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## AaronT

ddavila06 said:


> Hey Aaron, since he wanted to keep his africans and at the same time have plants maybe we can suggest some hard water-high ph resistan plants? i don't know much on that subject, but i think anubias and ferns will do well, that if attached to rocks and/or wood, right?


Right, but I got the impression the original intent to keep African cichlids was no longer the case?


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## RapidSixGuns

thanks damian and aaront for the advice. let me 1st qualify myself as a beginner and novelist compared to the knowledge and experience of many of the members here. having said this, my original intent was to keep african cichlids hence the crushed coral. actually, this tank has been cycling for over a month now having only 3 goldfish in it. it wasn't until recently (about 3 weeks or less) that i developed an interest in live aquatic plants. i normally use artificial plants. of course i immediately thought i could use several plants that the members use here to beautify my tank but now i know this is not the case. aquatic plants like fish have their own requirements and perameters. however, certainly there are some aquatic plants that will co-exist in a african cichlid biotope. i've done a litle checking around and found that many of the plants used by members here can live in the perameters i have in my tank providing i do some modifications. the pH found in my crushed coral tank is only slightly above the top end of many aquatic plants. i'm guessing the main limiting factor is hardness and alkalinity. fortunately, this is not the only aquarium i have running. i do have 2 10gal.'s with bio-substrates in them. i hope to find a bigger tank (such as a 30gal or 40gal. breeder) so that i can combine the 2 ten gallon tanks. seriously, i really didn't mean to cause such a stir with the usage of crushed coral substrate but that was what i had and i wanted some live aquatic plants. i will be sure to start my next tank properly if i'm going to have the beautiful and flourishing aquariums many of you have now and use the plants primarily found on this site. BTW, not only do i find the aquariums here beautiful but i also find the creativity in the usage of oddball items (such as using a candy bin) to create biotopes and the imagination to build structures (such as a waterfalls). 

thanks again for the tips and advice,
rapidsixguns (aka michael)


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## 90gal

AaronT said:


> Crushed coral is an inappropriate freshwater planted substrate. It might grow some hard water loving plants well, but your selection will be severely limited. You'd do well to get a plant specific substrate or even just an inert gravel to start with. Why start with a handicap from the beginning?


I think it's important to realize that this guy is a beginner for live plants; and now understands what is optimal versus what is acceptable. Not everyone wants to spend $150 on substrate. Maybe the guy doesn't want a heavily planted tank with red colors abounding, maybe he doesn't want to dump $2k into developing a 100 gallon planted tank, maybe the tank isn't going to be the main focal point of the house. Folks here need to realize that maybe not everyone have their planted tank as their top financial priorities; and for some folks, it's a HOBBY and not a life-changing event.

I think he gets it - increased $$ = increased proliferation (better filters, higher WPG, super substrate, Co2, etc...). Although at this point; guy wants simple advice. How about passing plant-specific recommendations on what is acceptable for what he has?


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## Diana K

Go ahead and start with the crushed coral. It has worked for me in a couple of tanks. Simply go with the more adaptable of plants, and plants that thrive in hard water. 
Sure, you may want to add some fertilizer tablets, but you are getting started!
In fact, the fine material of the crushed coral may be a good one to allow the mulm to accumulate, yet is coarse enough to allow water movement to bring oxygen to the lower areas of the substrate. 

Plant that thrive in hard water:
Several of these are from Diana Walstad's book Ecology of the Planted Aquarium, pp 114-117 and 133
Most species of Valisneria
Hornwort
Myriophyllum spicatum and others
Elodea canadensis
Bacopa caroliniana (from a soft water in nature, but thrives in hard water, too)
B. monnieri
Saggitaria graminea
Ludwigia repens
Potemogeton pectoralis

This is by no means an exhaustive list, simply a comment that there are plenty of plants, whether originally from hard or soft water, that will do just fine in hard water. 
There are a few specialty plants that will not adapt, but these are not usually commonly available. At our local aquarium plant club a few members grow these plants, and are very specific when trading them that they are for soft water only.


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## Newt

I have to agree with AaronT and Geeks15. It just doesnt work well for a planted tank. Its your tank and if you like the looks of crushed coral and shells for substrate by all means try it. Just remember, you will not have control over what and how much leaches into your water column.


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## billb1

Actually you will have some control over how much CaCO3 goes into solution. It is pH dependant. If you plan to use it, just pick from the list of plants that Diana suggested and do not use CO2. CaCO3 will be pretty stable at a pH of 8 and higher. Below 7, you will get significant amounts disolving. If you use pressurized CO2, you will see a steady increase in TDS. 

Plants like Vals, are able to utilize bicarbonates as a carbon source for photo synthesis and will not need to supplement.


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## AaronT

90gal said:


> I think it's important to realize that this guy is a beginner for live plants; and now understands what is optimal versus what is acceptable. Not everyone wants to spend $150 on substrate. Maybe the guy doesn't want a heavily planted tank with red colors abounding, maybe he doesn't want to dump $2k into developing a 100 gallon planted tank, maybe the tank isn't going to be the main focal point of the house. Folks here need to realize that maybe not everyone have their planted tank as their top financial priorities; and for some folks, it's a HOBBY and not a life-changing event.
> 
> I think he gets it - increased $$ = increased proliferation (better filters, higher WPG, super substrate, Co2, etc...). Although at this point; guy wants simple advice. How about passing plant-specific recommendations on what is acceptable for what he has?


I certainly wasn't suggesting he spend hundreds of dollars, only that the crushed coral isn't ideal, even for many of the nicer beginner plants such as Ludwigia repens and Rotala rotundifolia, both of which are usually staples for beginners and often found easily in stores. My point is to help give him the greatest chance of success.

Any cheap inert gravel would suffice better than crushed coral in my humble opinion.


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## seove

I naively added several pounds of crushed coral to my sand substrate some years ago and I have to say that the plants don't like such a high pH. I have a hard time lowering the pH. The plants struggle in it. I should start trying to remove some of the CC.


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## Diana K

Every time you get the pH a bit lower more coral sand will dissolve. It dissolves best in low pH. As more dissolves, the pH rises. 
If you do not like this chemistry, then redo the tank. Get rid of all the coral sand. You are not going to get anywhere trying to lower the pH while the coral sand is in the tank.


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