It is important to understand that products like boric acid and diatomaceous earth are only going to work on those ants that actually come into contact with them. The majority of ants live in cracks, crevices, and wall voids, nesting locations, etc., and will only come out when absolutely necessary. Boric acid and DE have nothing in them to actually attract the ants, so they must be strategically placed into the places where ants live, and it will take several days for them to actually die after they ingest these types of products.  During this time they can continue to breed. We would recommend using an ant bait gel, ant bait granular, and an insecticide spray for faster results.  You may want to take a look at our Ant Control Kits, which contain all of these products. Please take a few moments to review our article and videos on How to Get Rid of Ants for a successful eradication program. Taurus SC would be a great exterior foundation spray (1 ft up and 1 ft out) twice a year.    

We highly suggest you read over our detailed article called "How to Get Rid of Ants".  This gives a detailed breakdown of what steps to take for treating whether using baits or sprays and where to look for nesting sites. The baits in our Outdoor/indoor Ant Kit really are the best option as you will not put them IN the shower, but near and around the shower for them to go to. They are looking for food and water so just because you see them IN the shower when you find them, doesn't mean they wont leave it to get to a food source. The ants cannot eat the bait in the form its in so they take it back to the colony to be broken down first, and then dispersed to the queen and workers to eliminate the entire colony at its source. This does take time but its the most complete way of getting rid of them. 

We have various kits that are labeled for ants. Our Outdoor/Indoor Ant Kit comes with all the products that you will need to do a complete ant treatment.   STEP 1 - BAIT INDOORS - Bait Plate Stations, Advance 375A Granule Bait, Maxforce FC Ant Bait Gel *Handle bait stations with clean, dry hands or wear gloves. Avoid handling bait with bare hands as this may make baits less palatable. *Your kit includes a set of 12 bait station bases, 12 lids, and 12 glue dots. Pull apart the stacks to separate the components. Each base is a tray with two ridged channels so that you can use two different baits in each bait plate station. *To apply the Advance 375A Granule Bait, unscrew the top, then either gently tap the granules into a bait plate station tray, or use a dedicated or disposable tool such as a plastic spoon to scoop the bait into each station. Use 0.3 oz.- 1.0 oz. of bait in one side of each bait plate station you plan to set out. (Keep the other channel empty for the gel bait.) *To apply the Maxforce FC Ant Bait Gel, first gently unscrew the solid black tip of the tube you would like to use. Replace this tip with one of the clear, reusable tips included with your kit. Use either a bait gun or the included plastic plunger to gently expel the gel from the tube, similar to using a syringe. (You may need to pull back gently on the plunger to prevent over-application.) Place a spot of bait about the size of a pea in the other side of each bait plate stations you plan to use. *When you are done applying the Maxforce FC Ant Bait Gel, replace the clear plastic tip with the black solid tip to store bait. *After you have filled your bait plate station trays, snap a lid onto each one by lining up the U-shaped tab and the round tab with the corresponding parts in the tray. Gently press the edges of the lid until it is firmly snapped into the tray, being careful not to tilt the trays, which may cause granule bait to spill. It is not necessary to remove the perforated tab from the bait plate station lids. *You should place bait in areas where ant activity has been noticed. It is important to avoid purposefully putting the bait in the middle of an ant trail or onto the ants themselves: this will make the ants avoid the bait and make the baiting ineffective. Instead, put the bait near ant activity or next to ant trails. Some examples of places where the bait can be placed are: In kitchen cabinets and on counter tops. Behind, next to, and under the stove. Near sinks or drains Around pipes, cords, and cables that come out of the wall. Behind and under bathroom fixtures. Around the medicine cabinet and vanity. *You should check the bait placements once a week and replenish as needed until ant activity has ceased. Be sure to continue reapplying bait as long as the ants accept it! *Store baits in a dry, temperate area, out of direct sunlight. Baits are best used within a year of opening. *Bait stations may be wiped clean and washed with warm water for reuse later. Do not use fragrant cleaners, as this may make future bait applications unattractive. STEP 2 - SPRAY INDOORS - Phantom Aerosol Spray *Phantom aerosol is a non-repellent ant spray that will have effects similar to those of your ant baits. Although this will take a little more time to start killing the colony, it is a great companion and backup for when ants may not be actively foraging for food. *Phantom can be used with the wide spray nozzle or with the included white nozzle and black crack and crevice straw. We recommend applying Phantom with the straw to make more detailed applications. If you have trouble inserting the straw, you may need a pair of needle-nosed pliers to force the straw into the nozzle. (Be sure to do this while the tip is off the can.) *Apply Phantom to cracks and crevices where ants are likely to enter the structure or to trail, such as around window frames and door frames, where pipes and other utilities enter the structure, in corners, under appliances, and in any other spots where ants may have access into the structure. *Keep other people and pets out of the treatment area until the spray has dried. *Do not spray Phantom or other insecticides directly on top of bait placements. *Phantom may be reapplied if needed, but wait at least 4 weeks between applications. STEP 3 - SPRAY OUTDOORS - Termidor SC *Termidor SC is a liquid concentrate that must be diluted with water only and applied with a sprayer. *Termidor is a non-repellent spray, meaning it has an intentionally slow kill on the individual ant. This gives the ants time to spread the active ingredient throughout their colony through their regular social and food-sharing habits. *Shake the bottle to make sure the concentrate is ready to dilute. The tip-and-pour bottle makes measuring simple: with the label facing you, simply tip the bottle to the left so that liquid fills the small reservoir up to the 0.8 oz. line. Use 0.8 oz. of concentrate per gallon of water in your sprayer. When you are ready to pour, unscrew only the cap on the angled small reservoir. *To dilute the Termidor SC, fill your sprayer tank 1/3 - 1/2 with water, add Termidor SC, and gently agitate the mixture. Finish filling the tank and agitate again prior to spraying. *Make only enough solution to use for your current application. Do not store spray solution in your sprayer since it will degrade quickly and may damage the sprayer seals. Most outdoor applications will require 1-2 gallons of finished solution. *Apply Termidor SC solution around the foundation of the structure, creating a barrier one foot out on the ground and one foot up onto the building itself. Also spray areas where ants may enter, such as around window frames, door frames, places where cables, pipes or wires enter the structure, and any other place where you have noticed ants crawling or trailing on the structure. *If you are using baits outdoors, do not make spray applications directly on top of bait or bait stations. *Do not broadcast Termidor or apply in the yard away from the structure. *Keep people and pets out of the treatment area until the application is dry, usually about an hour. *Do not spray on edibles such as vegetable gardens. *Termidor applications are limited to twice annually, so most folks choose to treat once in the spring when activity begins, and again in late summer or early fall, if needed. *Store concentrate out of direct sunlight and in a temperate area for up to 3 years. STEP 4 - BAIT OUTDOORS - Ants No More Bait Stations, Advance 375A Select Granular Ant Bait, Maxforce Quantum Ant Bait *Allow spray application to dry before placing stations. *Always use bait in clean, dry bait stations. *The Ants No More Bait Stations are designed for discreet outdoor use, protecting bait from rain, sunlight, and non-target animals. The two interior compartments allow you to use two different ant baits in each station. You will apply the Advance 375A Select granules in one side, and the Maxforce Quantum Ant Bait in the other side. *This kit contains 12 bait stations, but you may not need to use all of them at once. Stations should be place approximately 25 feet apart, so most homes may only use 4 stations around the perimeter of the structure. Stations may be placed in other areas of high ant activity, keeping in mind that it is neither necessary nor ideal to eliminate all the ants from an outdoor area. *To open the stations, line up the arrow on the cylindrical body (there is a dip in the station) with the center mark on the lift tab of the lid. *Push up on the lid, then push back on the opening so the lid can pop up. *Apply up to 1.5 oz. of Advance 375A Select Granular Bait per station (each side of the station holds 2 oz. of bait). You should not fill the granules all the way to the top of the compartment to prevent excess condensation buildup. *To use the Maxforce Quantum Ant Bait, first remove the blue cap from the tube. For your first application, you will need to cut the tip of the tube with a knife or sharp shears to create an opening. Cut approximately ¼ in. from the tip to create an opening about 1/8 inch in diameter. *The Maxforce Quantum Ant Bait may be used as is, or it may be mixed into a sugar solution to create more bait. We recommend making the following mixture to get the maximum use out of your bait: You will need clean water, bait, granulated sugar, a container for mixing, and either a lid to cover and shake the solution or a spoon or other tool to mix the solution. To make enough solution to fill one compartment in each of 4 stations: in 8 ounces of water, mix 1 ounce (30 g) of Maxforce Quantum and 2 ounces of sugar. Distribute evenly in each station. To make enough solution to fill all 12 stations: in 24 ounces of water, mix 3 oz (90 g) of Maxforce Quantum and 6 ounces of sugar. Distribute evenly in each station. Do not store extra solution more than a few days since bacteria and mold may develop. *Replace the lid on filled stations by popping on at any orientation. *Place stations in the ground up to the first entry and exit holes in the stake. *Check stations after a few days to determine if placements need to be altered or bait needs to be replenished. *If baits appear moldy or granules are wet and puffy, replace with fresh bait as needed. *Maxforce Quantum also comes with 10 refillable bait stations. Maxforce Quantum can be applied in these stations by placing a small amount (do not overfill) in one or more of the small interior compartments, then closing the station like a book. Be sure the lid is secure, then place stations in areas of ant activity such as near trails or nests, near the foundation, or along fence lines. Replenish bait as needed. *Bait stations may be wiped clean and rinsed with water as needed. Avoid using harsh cleaners or fragrant soaps as these may make baits less palatable to the ants. *Store baits in a dry, temperate area, out of direct sunlight. Baits are best used within a year of opening. - See more at: http://www.domyownpestcontrol.com/outdoor-indoor-ant-kit-p-14505.html#sthash.PRtaGmsq.dpuf