substrate questions

[Kittycat]

You guys must be sick of this question, but I need your help. I can't decide between using gravel or sand. I have read conflicting info re: sand for planted tanks, some say plants don't do too well, some say it's best for plants. Are there any particular types of sand that is good for plants, and bad for them?

I'm concerned as well about vacuuming. From what I hear, heavily planted tanks with gravel don't need to be vacuumed. Is the same true if sand were used, considering that the dirt/poop will not go under the substrate but stay on its surface?

Also, what is the best procedure to convert an existing, established bare tank into a planted one? How do you clean your substrate before putting it in the tank?

 

[George Farmer]

Here's what I know about substrates! Mods - Do you want to pin this?

Substrate

It is worthwhile spending some time (and money) in setting up the substrate well from the start, as it will be very awkward to make changes once it has been installed.

A good substrate is often over looked in my opinion. Although perhaps not as important as light, it is essential for the long-term health of plants especially root feeding species i.e. Echinodorus species (Amazon Swords) and Cryptocoryne species (Crypts). It must provide a number of functions; an ideal medium in which the plants can be anchored, provide nutrients to the plant roots and provide a breeding ground for beneficial bacteria.

It is important to have plenty of nutrients in the substrate. In a new aquarium, standard substrates i.e. gravel or sand will be virtually sterile. Most plants, especially root-feeders will not grow well in such substrates initially. Over time the substrate will accumulate detritus and this will provide some nutrients for the roots (this may be limited with sand as the small granule size allows only limited penetration). There are substrates specifically designed for planted use providing useful nutrients from the start. These can be expensive but very effective. Another cheaper way is to use gravel additives or root fertiliser tablets.


Types of Substrate

Gravel - Probably the most commonly used substrate. It can be various sizes from 1mm right up to 20mm or more. Fine gravel (1 to 3mm) is ideal for most plants as it allows the roots to penetrate easily, larger sizes and it becomes too “heavy” and may limit the root’s growth. Caution must be taken with some gravel as they may contain lime (CaCO3) and will slowly increase pH and hardness levels in the water. This is especially a problem in soft, acidic water, as the gravel will leech CaCO3 at a greater rate. A common method of testing if the gravel contains lime is to place some in a test tube (or similar) and fill with a strong acidic substance. If the gravel “fizzes” then it contains lime.

Sand - Sand is becoming more popular in the hobby. It gives a pleasant, natural look and allows the plants to anchor and grow effectively. One major downside is that it may compact over time, possibly blocking the roots and creating anaerobic “dead-spots”. This problem can be prevented by regular loosening or sifting of the sand or by using a heater-cable. Substrate additives are beneficial as sand is generally sterile. Avoid sand from the ocean as this will alter water chemistry increasing pH and hardness.

Soil - Quite a controversial substrate but I have heard of many success stories with it. Normally the lower third of the total substrate is soil and a top layer of gravel or sand must cover it effectively preventing the excessive nutrients reaching the main water column. Substrate additives must not be used as these will create too many nutrients. Heater-cables must also not be used as this will allow the excess nutrients to enter the water column. I do not have personal experience with soil substrates but I understand that they are used more in low-tech set-ups

Specialised - Substrates that are designed specifically for planted use are possibly the most effective (and expensive). They contain a lot of beneficial nutrients and will stay fertile for long periods. Substrate additives are not required. Examples are Carib Sea Eco-Complete, Seachem Flourite and Dennerle Deponit. These can normally be mixed with a plain substrate to save on cash.

Substrate Additives
If using a plain substrate like gravel or sand then additives are an effective way of providing nutrients. Commonly used additives include laterite and clay type substances that are rich in usable (bi-valent) iron. Normally the additive is mixed in the lower third of the substrate. This prevents the excess nutrients from entering the water column.

Substrate Heating
This is normally achieved using a heater-cable that runs along the tank base in a zig-zag pattern attached with suckers. Obviously it requires installing prior to adding the substrate. Various models are available varying in lengths and power consumption. Allow 1 to 3 Watts per 10 litres of water as general rule. The more expensive models work in tandem with the main aquarium’s heater/thermostat. Cheaper models are “on” all the time but can controlled via a timer so a stable temperature can be achieved.

The action of the heater-cable provides a small temperature difference between the substrate and the water above it. This produces a small convection current and converts the entire substrate into an effective biological filter. The warmth provided also stimulates root growth and prevents the substrate from becoming anaerobic (devoid of oxygen). One possible consequence of an anaerobic environment is the production of Hydrogen Sulphide, a foul smelling substance that is toxic to most life. In my view, substrate heating is almost a necessity for the long-term health of the entire aquarium, plants and fish alike. The benefits are great and far outweigh any possible disadvantages in my opinion and experience.

 

[pica_nuttalli]

sorry to post dig, but this seems like something worth bringing back up again... i'm hoping to set up a planted 10g in the next week or so. i want to get the substrate right for once, so i've got the following questions;

( 1 ) what exactly is the difference between Flourite and Laterite?

( 2 ) which would be better to use with a sand substrate (with burrowers like loaches)?

( 3 ) whats the shallowest depth of sand that would work for rooted plants such as crypts or swords? shallowest depth of gravel?

( 4 ) at what depth of substrate does a heating coil become necessary?

 

[George Farmer]

sorry to post dig, but this seems like something worth bringing back up again... i'm hoping to set up a planted 10g in the next week or so. i want to get the substrate right for once, so i've got the following questions;

( 1 ) what exactly is the difference between Flourite and Laterite?

( 2 ) which would be better to use with a sand substrate (with burrowers like loaches)?

( 3 ) whats the shallowest depth of sand that would work for rooted plants such as crypts or swords? shallowest depth of gravel?

( 4 ) at what depth of substrate does a heating coil become necessary?

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That's a blast from the past! I remember being quite annoyed that Kittycat didn't even respond to my reply. A thankless task sometimes!

1. Put simply laterite is a concentrated form of nutrients (mostly iron) and is therefore mixed/diluted with plain gravel or sand. Flourite I believe has a more comprehensive make-up of nutrients with a lower concentration so can be used solely as the substrate or mixed i.e. 50:50. Laterite is cheaper.

2. Either would work. Normally laterite is mixed in the lower third of the substrate. I've not heard of people mixing flourite with sand, but it should work. My only thought would be that eventually the sand would compact and sink underneath the flourite - this shouldn't be a problem though.

3. I'd say 3 inches minimum for root-feeders with either sand or gravel. I'd be inclined to choose gravel (1 to 3mm grain size) over sand for root-feeders though. The roots should experience less resistance with a fine gravel. Sand can compact over time as described in my "article" possibly blocking root growth.

4. There's no set depth as far as I know. There use is now considered completely unecessary by some although I still beleive it benefits my tank. If you plant heavily enough then the roots should provide enough oxygen to prevent possible big dead-spots and hydrogen sulphide build-up. If you can afford one then I recommend buying one anyway - they certainly don't do any harm.

Hope this helps. Did your Algae-eater article get well recieved BTW?

 

[Teelie]

She might not have been thankful but I am. I'm looking into trying a planted tank again after my last attempt went from great to crap over the course of several months. I had plant root sticks that were meant to feed plants for a year or so and they did their job, it just didn't last a year. I think I'll try something else like laterite and deeper sand. Mine was approximately 1.5" overall with more depth around the plants themselves but I guess it didn't quite work out. Plus now I have trumpet snails to help sift the sand so I won't be so concerned with gas build up.

One thing though that I haven't found yet; what plants do best in sand? I had apongentons, lilies and banana plants last time which all started out great then abruptly died. The apons I should've taken out I know for winter but the others I thought could've stayed.

 

[pica_nuttalli]

heh, i need to revive the picture request so i can get that sucker finished and pinned.

thanks for the quick reply! now i can really get this bad boy started. B)

 

[zig]

Here's what I know about substrates! Mods - Do you want to pin this?

The irony

But a good idea IMO